i was thinking about adding a point system to one of my sites the users can buy a lottery every month and win real cash also once the users have high credit they can turn that into real cash there is no way to buy credit, the users can only get them by participating is it ok to do this?
What kind of gambling is being done? Also when you say buy a lottery, do you mean with the points that they've earned or do you mean buy with real cash?
If money is being exchanged (in any round-about way) for a chance to win something of value, it's gambling. Also, you'd be wise to check out the lotto and raffle laws of the state you are in and the states in which your participants are in. It's your responsibility to void and disallow participation in those states where your operation is in violation of their laws. And yes, even if you were to do a free lotto, you'd have to limit playing from some areas.