I just remembered that I actually have a PLA rubber stamp already. I got it in the late 90's to stamp PLA merchandise envelopes with before I owned a decent printer to make labels. It looks really old and has a wooden handle on it. It's not self-inking. Here's what it stamps like:
It looks kind of messy on the right side. It's been in storage for a year in Illinois so maybe the cold cracked it. I took a knife and chopped off the address part. It's not really ideal for stamping dollars still, but it works:
Click on that one to see a whole page of bills. I couldn't make it fit very well on any of my money. We might want to go with something that doesn't have the logo. Then again, I guess it doesn't really matter if the logo doesn't show on bills. Something like this should work:
It only matters that the words fit. Or I could do something like this:
Which could just be stamped along the edge of any bill.
If you do decide to put these into merchandise (or at least the ink pad kind since they're cheaper), I'd promise to buy a small shirt if you send me a stamp for free since I suggested it
I'll give you a free stamp even if you don't order a shirt. In fact, if you want this one I already have, PM me your address. Though you might want to wait since this one probably isn't as good as the new ones I'll get made.