I've got a vinyl cutter if you want to stick to a single color cut vinyl decal/sticker.
If you want some advice, I'd go with something that fits in a standard sized envelope to make mailing simple and easy (and cost effective). You also want to be careful that you don't go too small on any of the text or graphics if you do cut vinyl - too easy for some parts of the graphic or text to fall off over time - like from washing them.
Lots of choices on vinyl out there, but it may be best to stick to a few colors if you are going to try and do these in bulk - white, black, silver, pink, maybe a silver reflective too?
Sadly the printer/cutters are still a bit too pricey for my hobbyist budget. Let me know if I can be of help -
kevins_garage@yahoo.com.