I would just go no name British with steel barrels, nitro proofs and 2 3/4 chambers like this boxlock that has been sitting on Gunbroker for at least two years:

http://www.gunbroker.com/Auction/ViewItem.aspx?Item=533887367

I also bought a nice LC Smith field grade featherweight a few years ago for $300 at a pawn shop that I enjoyed immensely. Had the stock glued up and then had no issues with low pressure loads through it. Only had $400 into that one.