It's common here, too, so i wouldn't jump to the conclusion that it's a briticism. my best guess at its etymology would be something along the lines of this:
you put a token in a machine and you get one of various 'prizes' ~ all from the same machine, all of relatively equal value, but all deriving from the same (or similar) token. i think it just represents the mental (or verbal) process of offering a token--or path of thought--and coming up with varied (but comparable, and similarly derived) responses.
