Great way to disrupt the postal system! It's a legal gray area, but you would only be against it if you're against innovation and new technology! I'll call it Stampr.

I'm pretty sure there isn't much gray area in defrauding the postal service.

A "hack" would be to switch the sender and receiver addresses on the envelop; and mail without a postal stamp. What is the postal service supposed to do with an envelop missing the stamp? Yes, you are right. Return it to the sender.

Reminds me of when we would make collect calls from a payphone and our parents would get: "Will you accept a collect call from...MomPickUsUp"

Haha that reminds me of a similar hack we discoverd as kids. Australian payphones had an interesting feature where you could place a call without paying however the call would hangup almost immediately upon being answered. There was a split second where you could actually hear each other so we'd usually yell something out and our parents would know it was us waiting to be picked up from the beach or some such.

My Mom's family had a different solution. At 7 o'clock, call. If you let it ring once then it means pick us up now. If you let it ring three times, then pick us up in an hour.

Thinking about it now, Skype gives rings on the caller's side even before it's connected on the receiver's side. In that case, use synchronization. If it takes between 1 and 4 caller rings for the receiver to ring, then a call at 7:00 means "come now" and a call at 7:05 means "come in an hour."

When I was 9 I used to send my SASE and $.50 or so off to various mail-order companies. They required that you put your own address as both the return-to and destination on the SASE...through absentmindedness I soon discovered that the stamped part of SASE was optional.

In the UK, they don't do this - they send it on to the recipient, but hold the mail at the office until the recipient travels down there and pays postage plus a £1 fee.

I did this a while back as a test; it traveled two hours away without postage, despite both recipient names being the same.