pawn shops are going to be your best bet... unless you check out ebay and try to get a good deal on something... but as a good general practice it's never good to buy something you can't try...... especially amps and guitars since they're such high price investments.

maybe check out your local guitarcenter and look at some of vox's valvetronix modeling amps... there technology is coming pretty darn close to getting good all around tube tone and response... they have two kinds now too.... one for hjigh gain tube modeling and classic brit and us tube modelling. be worht a shot