The Postal Service laments the fact they're losing money like crazy. Yet, there are ways they could bring some more back in. USPS, feel free to use these ideas.
The Elvis stamp made money as millions were kept and never used to mail anything. There are other stamps that would be hits. Famous UFO crashes. Drawings of places where UFOs crashed would be gobbled up by the UFO crowd. Just imagine a first day of issue cover from Roswell.
Hold local raffles if you have a hot mail carrier. "Win a date with your letter carrier." That would be popular.
Mail your kid to grandma. Just like it sounds, if kids meet certain size limits, parents could mail their kids to another relative in specially marked boxes--with air holes of course.
Sell ads on the side of mail trucks. Hey, it works for buses. Don't know why they haven't tried this obvious one before now.
Sell seats on mail trucks. Not the local delivery ones--the big ones that haul mail along the interstates. There's a passenger seat just going to waste.
Prizes in stamp books. You buy a book of stamps and scratch off a coupon inside and win prizes like cash, or stamps or your picture on a stamp.
Well, these are a few things they can get started with. I'm sure I'll think of more ideas.