I've gotten a lot of comments on this Zero Per Gallon "$0.00 9/10" patch on my bag.
Most people "get it" except for a few uptight engineer types that are a little too literal minded. Actually, I think they get it too, they just like being dweebish pinheads.
These iron-on patches are $5 each. You can also get stickers for $2 each (cheaper in quantity). The stickers are also available denominated in Euros and burritos.
Zero Per Gallon now also takes bicycle tires and recycles them into belts that you can buy via his site.
I don't get a penny for promoting Johnny's patches and stickers; it's just cool stuff that I want to mention. Buy it at Zero Per Gallon.