I already ever experienced something like that and its not too pleasant, the site did give a sign up bonus, but it need to be wager with 40 times with limited time, it is so hard to wager 40times because I keep on thinking to win, it clouded my judgement and I am losing my bet, so I don't really excited about the sign up bonus
The signup bonus actually do not need the free money to get into your wallet. It actually mean the free credits for your game. It is given to you so that you play for a while on that website for free to learn the tools and buttons on that website and then you can feel convenient with your own money on that website.