This is a great option for mailing all those junk era Fleer and Donruss sets! Large Flat Rate Box (12x12) You will just need a bit of packing material at the ends to keep the boxes snug. The longer, thinner Medium Flat Rate box will hold three 660 count boxes almost perfectly. With a reasonable amount of bubble wrap and cardboard spacers, this can be an effective way to ship bulk commons, and base. It will also hold approximately 2,000 stacked cards. You will need some packing material to fit around the boxes to keep them secure during shipment. The more cube shaped Medium Flat Rate box can be used to ship four 400 count boxes. You can easily fit two 330 count boxes in a Padded Flat Rate envelope. The postage cost is very close to the small flat rate box, but they hold quite a bit more. These envelopes are not typically found in your local post office, but they can be ordered for free from the USPS website. Next up is the Padded Flat Rate envelope. I use team bags sandwiched in cardboard or snap cases, and then I put them in the Size 000 and Size 00 padded bubble mailers most often. You can usually get roughly 100 cards give or take in a first class package before it crosses the 16 oz limit. Just because you go beyond ten cards doesn’t mean you need to jump up to a priority package. I won’t go into the specifics here since I already covered them in The Definitive Guide to PWE Shipping. You can typically safely send up to 10 inexpensive cards via PWE. People continue to debate the appropriateness of shipping via PWE, but I continue to hold the position that there is a time and place for PWE shipping and it is the single greatest tool to allow you to make a profit selling low end cards.