I've done a bit of busking - I don't use an amp for vocal reinforcement, but I've used it for amplifying an electric guitar - that was the way to save my FINGERS from damage (I can't play with a pick - it ends up on the floor or in the soundhole in seconds). I used to use a small Vox amp - it was possible to buy Pignose amps at inflated prices, and while battery powered Fender Champs may have been produced they never seemed to get to GB twenty years ago. If I were you I'd be looking for any of these, second hand .