USPS Medium and Large Flat Rate Boxes: Stay Away!

Learn why taking advantage of Priority Mail Cubic can often save you more money than using free USPS Flat Rate packaging
stay away from flat rate boxes
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If you’re a normal human being, your ears probably perk up when you hear the word “free.” We’ll admit it…ours do, too. However, sometimes the free option isn’t the best option. This is especially true in the case of USPS Priority Mail Medium and Large Flat Rate Boxes. Even though USPS offers these boxes for free when shipping Priority Mail Flat Rate, they can still end up being almost $10 more expensive than using your own box! Simply put, using custom-branded packaging saves you money AND creates positive unboxing experiences for your customers at the same time. Like the old saying goes: “You get what you pay for.” In this case, springing for custom-branded packaging instead of free USPS boxes pays off handsomely.

Table of Contents

Why are Medium and Large Flat Rate Boxes Free?

Good question! To speak frankly, it’s essentially a marketing ploy (isn’t everything?). USPS came up with the idea to offer these particular boxes for free, along with a simple pricing structure to make shipping seem more approachable – they noticed shippers were having a hard time choosing the right USPS mail class. And guess what? It worked. Shipping Priority Mail Flat Rate has become widely embraced by small businesses across the country because they’re drawn to the free packaging. However, while small businesses think they’re getting a good deal, this practice often ends up hurting them. If you’re running an eCommerce business, you should steer clear of these free USPS boxes. Instead, a better option is to use your own packaging or create custom packaging for your products so you can take advantage of more cost-effective USPS services that exist.

Why Should I Use Custom-Branded Packaging Instead of USPS Flat Rate Packaging?

This question comes with a two-part answer. The first part of the answer is simple and quite obvious: it enhances the Customer Experience. The second part has to do with the cost. While Medium and Large Flat Rate boxes may be free, using your own packaging is often cheaper than shipping Priority Mail Flat rate, thanks to a “secret” USPS mail class called Priority Mail Cubic. Let’s dive into the details.

Customer Experience

Today, consumers care about experiences more than ever—and that includes the unboxing experience! Simply throwing your product into USPS branded boxes is a missed opportunity to reinforce your brand and strengthen customer loyalty. Therefore, if you want your eCommerce business to have a shot at competing, you should ALWAYS utilize custom packaging. Using custom-branded packaging is already common practice with nearly every successful eCommerce business out there. If you’re not doing it as well, you’re behind the curve.

Millennials Matter!

Speaking of strengthening customer loyalty…let’s talk about Millennials for a second. According to Forbes, Millennials officially have the most spending power out of ANY generation. Also, studies show that Millennials care just as much about the unboxing experience as they do the contents of their packages. Millennials would rather receive products in a nice custom package than in a less-than-aesthetically-pleasing USPS box (no offense, USPS). Therefore, if your eCommerce business isn’t using custom packaging, you’re not tapping into Millennials to the best of your ability. And if you’re not tapping into Millennials, well…you’re just sleeping.

Pro Tip: Check out our Reviews page for some custom packaging options!

Priority Mail Cubic: The Secret Sauce

Here’s the second part of the answer: custom packaging is often CHEAPER than Flat Rate boxes! We’ll explain how in three words: Priority Mail Cubic.

Simply put, Priority Mail Cubic is undoubtedly the cheapest AND fastest way to send small packages that weigh up to 20 pounds with USPS. This mail class is so deeply discounted that it’s often cheaper than shipping Priority Mail Flat Rate, even after you factor in the cost of custom packaging. Here’s how the cookie crumbles. Shipping Priority Mail Cubic gives you the opportunity to save money and build customer loyalty at the same time. It’s a total no brainer!

USPS Priority Mail Cubic Beats USPS Flat Rate Every Time

The truth is, shipping Priority Mail Cubic will be cheaper than Priority Mail Flat Rate—even AFTER you spring for custom packaging. Therefore, the free Flat Rate boxes are never a good deal, especially if you can ship Priority Mail Cubic with shipping software. Plain and simple, shipping Priority Mail Cubic is one of the cheapest ways to ship with USPS. Oh, and one more thing. If you’re really adamant on not spending money on custom packaging (which we definitely don’t recommend), you can get free USPS boxes for Priority Mail Cubic.

How Can I Ship Priority Mail Cubic?

Unfortunately, USPS doesn’t publicize Priority Mail Cubic, and it isn’t something the Post Office offers to everyday consumers. Typically, the only way to access this “secret” mail class is to enter into a contract directly with USPS. Those contracts have strict guidelines to meet, like shipping over 50,000 packages a year. Realistically, that’s a lofty goal for a lot of small businesses to hit, so Priority Mail Cubic discounts have mostly only been enjoyed by big commercial businesses in the past.

Fortunately, there are tons of shipping software options allows you to ship Priority Mail Cubic at the best Commercial Rates with NO hidden contracts, markups, or fees! That means you get the best USPS discounts and save a ton of money on postage…and that means your small business has a better shot at thriving.

If you’re looking for the best shipping software, you probably know by now that there are lots of different choices out there. While many of them offer the same services from the major carriers, some are more encompassing than others…and some are even cheaper than others. However, it’s up to you to do the research and figure out which one best fits the needs of your small business. To check out recommendations written by shippers like you, head over to our Reviews page!

Looking for the right shipping software for you?

To get the deepest discounts on USPS services like Priority Mail Cubic, check out our guide:

Choose the Best Shipping Software

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Post a Comment
  1. Jamie

    Lori….You do not understand what was being said. What the article meant was this:

    IF you simply go directly to USPS, you cannot get the Cubic Priority rate unless you reach that 50000 piece threshold.

    HOWEVER, if you use Pirate Ship, you have NO MINIMUM number of pieces to worry about. You can get the cubic rate from shipment #1. So it is NOT click-bait. It is a very real to save you money for shipping.

  2. Shella

    I also have to wonder if these “shipping partners” are cheaper because they’re SLOW! Seriously. I bought from a seller that everything he sent was with a partner that you could tell when they picked up from him & then when they actually gave it to USPS which had at least 10 days lag time. Stuff like that tends to piss off customers & is really NOT worth saving a buck & then never having that customer buy again AND ding you on ship time feedback. This particular seller? IL to CT should not take 3 weeks!! I have received stuff from CHINA in less time! Although with him it didn’t help that on 5 things ordered, one was wrong & when I offered to return the wrong item, but still wanted the correct item, he spent 2+ weeks arguing with me. So 3 packages when 1 would have sufficed! I didn’t send the wrong one back because he said it wasn’t his…

  3. Lori

    Why did you even start this article. The title is very deceiving. 50,000 boxes a year? 90% of your eBay people do not ship that many! I hate click bait. Thanks so much

    • Lynn

      It’s not clickbait just because you don’t sell enough.

  4. Special K the Potato Farmer

    Could I get an article on shipping things for cheap? No fuss, no min ship requirements, no small business ploy. Just find a box in the garage and send things to a friend?

  5. John in MN

    Cubic is only for small shipments, so most likely no shipping “water”. And you can NOT use free USPS Priority Mail boxes for Cubic rate. This whole article should probably just be deleted.

    • chris

      Um.. did you even read the article?? it specifically states not using flat rate boxes and using your own packaging and it also specifically states a max weight up to 20lbs… and then where to go to take advantage of this shipping method.. so this was actually helpful. Your comment should just be deleted. lol

      • Melissa A Louckes

        You are actually the one who didn’t read the article correctly. The author specifically states “Oh, and one more thing. If you’re really adamant on not spending money on custom packaging (which we definitely don’t recommend), you can get free USPS boxes for Priority Mail Cubic.”

        • Cyndi J

          This isn’t rocket science. It says the post office will provide boxes for PRIORITY MAIL CUBIC see below)

          USPS offers 6 free “mailing boxes” that you can use with weight-based Priority Mail or Priority Mail Cubic
          Pirate Ship avatar
          Written by Pirate Ship
          Updated over a week ago

          Priority Mail Box – 1096L | OD: 9.25″ x 6.25″ x 2″ | Cubic Tier 1
          Priority Mail Box – 4 | OD: 7.25″ x 7.25″ x 6.5″ | Cubic Tier 2
          Priority Mail Box – 1097 | OD: 13″ x 11.25″ x 2.25″ | Cubic Tier 2 *
          Priority Mail Box – 1092 | OD: 13.68″ x 12″ x 2.875″ | Cubic Tier 3
          Priority Mail Box – 1095 | OD: 15″ x 12″ x 3.125″ | Cubic Tier 4
          Priority Mail Box – Shoe Box | OD: 7.25″ x 5.25″ x 14.75″ | Cubic Tier 4

        • Jill

          There’s a link in ‘the get free USPS boxes’ that takes you to another page to order special boxes for the cubic shipment.

          • Will

            Thank you Jill…your comment here is the brightest one I’ve read.

        • Lynn

          Priority mail cubic isn’t the same as regular priority mail, and the statement you copied is the same thing that chris said. The article directly states to USE CUSTOM PACKAGING.

  6. NaZairea

    Considering the millennial generation is typically defined as being born between 1981 and 1996; most of the people reading this article are millennials. Which is 20s – 40yr old. You might not wanna be calling most of your audience ” lost souls who move back in with their parents after college.”.

    • Nadia

      Agreed. You can really tell the age of the person who wrote this article.

      • Joy

        You can tell the age of the person who responded OFFENDED too.

        • Bob Bicceroni

          Just because a person calls an article out on its BS doesn’t make them offended.

          • Lynn

            The article isn’t what’s bs, the fake outrage is. There is nothing bad about millennials here, and I am one so I would have noticed.

      • Angela

        So you could tell he was born in 1990? 🤔

    • Terry DeBord

      I didn’t read that.
      Is that what you read?
      Seems you got some kind of problem.

    • Henry

      I guess they have updated/edited this because I read your comment and there wasn’t anything negative about millennials in the article.. not anymore .. lol.. you talked.. they listened.. still bs article

      • Lynn

        There was never anything in it that was bad about millennials, it’s called fake outrage. And once again, article isn’t what’s bs here.

  7. susie

    USPS Cubic is called cubic for a reason. The item MUST be less than .5 cubic feet. This means, for example, 12x12x6″.

    • Peter W Watson

      Yours is the only useful information in this entire discussion.

    • R C

      Can u ship usps cubic from the pubicx grocery store?


    How can o ship water cost effectively

    • Rockwell Sands

      Hi Nerlyn, thanks for writing in! If you’re shipping bottles of water, you may get the cheapest rates with Priority Mail Cubic using online shipping software. You can also use free USPS boxes for this service, if you’re trying to keep costs down. Check out our Reviews page to see which shipping software might be the best option for you – I personally use Pirate Ship!


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