Gambling with the introductory offer from a betting website can earn you a few hundred dollars at a time

If you open an account with a betting website (Ladbrooks )and say get $50 free to bet with.

Then open an account with Betfair (to lay your bets off)

place a bet to win with ladbrooks and to loose with betfair. Hopefully betfair bet will win and you can instantly withdraw your money.

There's a little more to it than that, but if you do your research, it fairly easy to do. ive made money doing it before.

Good luck and hope this helps