Note that you can order n=10 packs of 10 PFREs + n=6 packs of 15 PFREs (i.e., both at the same time). Net effect is that you are able to get two cases of PFREs at once. The USPS system treats it as two separate items, even through they are the same thing....I have 30 cases of padded flat rate envelopes though. You can only order 1 case at a time so it takes a while.