Perhaps everyone else in the world knows about these, but I've only just found out. Apparently you can buy accurate looking mini-coins. My brother just gave me some, and they are very nice for my 1/4 dolls, but would probably be perfect proportioned of 1/3 sized.
I just thought I'd share in case anyone wanted their dolls to have their own currency! (Sorry for the blurriness, I'm working with a phone while my camera is out for repairs)
Caretaker of the Axelsen household: Aria, Annica, Aubrey, Azalea, Asher, Amelia, Alantril, Arivan, and Angora
I have some that I purchased at a rock & coin show a few years ago. They were in a pouch that said "small change." Har har har! XD I don't know who produces them, though.