We have bought good binoculars at pawn shops, on occasion. Be very careful that they are aligned if you go that route. And don't trust the person behind the counter to tell you, as they always seem surprised when we point out that they are un-aligned. You also might want to contact Chuck Hards, who has bought one of every binocular ever made (only a slight exaggeration), and can probably help guide you to get the least expensive, decent one, around. He also makes binocular mounts, and could give you guidance there, as well. Quoting Randall Peterson <rpeterson84010@yahoo.com>:

I bought bird watching binos at Sportsmans Warehouse on 72nd South - they had a bunch of different brands and models, all available to look through.