So you know no one is checking postage! Bubble pack envelopes are the cheapest to ship as most of the time the recipient gets the stamps to mail his next trade with.

My guess is that there won't be checking of postage on our light envelope shipments for months, if ever. Drop them in the mailbox... don't ask the clerk how much.

Realistically, it costs USPS more to check and return if short than just to let them go through to the recipient. Only a few cents involved in most cases.