In my own experience, which, granted, is not that extensive as far as selling birds goes, unless your roo is a good, proven sire; shown and won; or a specific, popular breed; you'll be lucky to break even. If you can get $20 for him, go for it. Just be prepared to accept a counter offer. If pullets and layers go from $15-25, and I could get him a good home, I'd accept $10 - or counter to $15.
Good Luck!
Good Luck!