: You can find flat rate boxes for sale on Amazon and eBay, though these are often resold or specialized versions.
: You can find boxes for UPS Simple Rate at The UPS Store . Unlike USPS, UPS often allows you to use your own packaging for their flat-rate service as long as it meets their size requirements. 3. Third-Party Retailers where can i buy flat rate shipping boxes
If you need specific types of boxes or want to buy in bulk from other sources: : You can find flat rate boxes for
: Independent stores like PostNet or Mail Boxes Etc. typically stock various flat rate options and can help with packing. where can i buy flat rate shipping boxes
: You can also order these supplies by calling the USPS Package Supply Center at 1-800-610-8734 . 2. FedEx and UPS