I'm a customer of betonline (tigergaming) and don't want to use coinbase, even through an intermediary wallet, because they can and will trace the account, so where can I sell my btc?
You can try localbitcoins, that is the usual go to of people that want to buy and sell bitcoins. Just beware of scammers though, there is a way that you still get scammed even if they deposited it on your bank account. Good luck.
Just curious though, why you do not want to use coinbase?
He cant because it is from gambling. He will lose all his bitcoin in no time there. They will easily make it disappear. That is in the terms of service of coinbase.
The best way is like how everybody dealt with it. Localbitcoins is the best idea or you can tell where you are from then we might look for a service that deals with bitcoin. But if not you should start looking for buyers of bitcoins at localbitcoin.