Do you want to make a gambling casino?
If you are, then I would say you aren't ready at all to make one. If you would be ready, you wouldn't ask a question like this. You would have already been prepared, with list of better questions.
Yeah, it is going to cost you a lot. You can buy one of those scripts to lower your cost, but trust me, no one is going to play over there. And forget about the bankroll. The bankroll is going to define how successful your casino is going to be. No one ones to bet on a casino with a max win of only 20 bucks.