Don't worry even if I said steal, this method is completely legal. I will write a short guide.
There are many online bookmakers who are offering sing-up promotions in form of a free bet or a bonus funds. They do this to attract new customers and it's possible to take advantage of these sing-up offers by using technique called Matched Betting.
Although it includes a word "betting" there is absolutely no risk like it's usually with online gambling.
The idea of this method is that you visit as many online bookies as possible and collect every singup promotion. But unfortunately it's not possible to just cash out these promotions, as these are restricted by different withdrawing restrictions, such as: bet X times to withdraw the bonus. So if you just bet in hopes of clearing the rules, it's very likely that you'll lose both - your deposit and promotion.
And here is solution to this:
To avoid these restrictions you have to bet two opposite bets in two sportsbooks - in the bookie where sing-up offer is and in the betting exchange. By doing so you can't win or lose anything, but you can fulfill withdrawing requirements. Make a few bets and promotion is yours.
Keep in mind that this is not some get rich quick scheme, but this works much better than all "Get Paid To.." stuff.
You can read more about this here:
No Risk Betting
Feel free to ask, if you have any questions.