There is quite a number of on line casinos giving players free money with no purchase required to claim. While some do require a small purchase before your allowed to cash out any winnings the credits will be given prior to any purchase.
At the site www.freeonline-casinos.net you will find a listing of these casinos giving players money with no deposit needed. Please read all the terms and conditions on the free promotions as they do have rules. Most will only allow you to play slots games.