It is not uncommon to come across a cover or card which has passed, or attempted to pass, through the mail bearing seals, labels, stickers, postal stationery cut-outs, revenue stamps, foreign stamps or what-not in place of "legal" postage stamps. Feel free to post examples here as you find time. These can include items which made it without penalty. were returned for postage, or sent forward postage due.
Here is an example I recently bought just cause it was neat.
1969 Easter Seal from RAMSEY NJ, 1969.
Sent forward postage due 6 cents which was the first class letter rate at the time.