If this is the place I visited a couple of years ago, I'd give it a miss. Bikes that are sold in a dirty state, covered in oil, mud, and rust, are most likely those that have been neglected, lack servicing, and are difficult to sell through normal channels. What you see is what you get. Caveat emptor, and all that. The bikes may well be cheap, but are unlikely to be good value, unless you are lucky.