I know what you feel like. I was in as swap not long ago and had used really small envelopes to sent out finished blocks, it cost me $1.74 per envelope, I was only mailing 6 at the time-35 would be mailed out in total. When I questioned the price the postal clerk said they had to charge differently since they could tell it was more than just a letter inside. I went ahead and sent those that day. A couple of days later I received a block from another swapper with postage due for the $1.74 rate-this seemed odd since most of the other blocks came back to me at $.44-$.64. So when sending out the nextt bunch I used larger envelopes 5x9 manilla ones and they all went for either 44 or 64 cents each. So I began using large envelopes and have watched my seams better-it has to freely slide through their slot card to go as a large envelope.