More than you’ll ever play. Somewhere between 100 to 500 or even more. Most of them use the same few wheels and live video footage provided by another company. So you can often play on the same wheel, but through a different online casino. The casino pays the live-video-provider a fee, but the casino itself is responsible for paying winnings. Although there are hundreds of live roulette casinos online, there are only about 30 different wheels.
One of the most well-known systems when it comes to betting on roulette is the Martingale strategy. It is a very simple doubling up betting system. For example, if you start off by betting £10 on red and it comes in black, double your next bet to £20 on red. You need to keep on doing this until it lands on a red and this will cover your losses. The only thing to think about before embarking on this strategy is whether you have enough money to lose before that first winning spin.
By the way, I want to take a moment to point out that this tidbit above about even money bets in Atlantic City is just one of the many fabulous bonuses you learn about for free on this site, which you might not find out about from books that cost actual money. When I was learning about gambling, the first thing I did was to buy and read the book The Complete Idiot's Guide to Gambling Like a Pro. But in 332 pages they didn't see fit to mention the low edge in Atlantic City, so I didn't know about it. I found out about it when an Atlantic City dealer took only one of my two chips on a losing bet and I had to ask why.
Even if there isn't a betting limit, and if you have an infinite credit limit, it still doesn't really work, it just doesn't really fail either. If the martingale strategy is continued indefinitely and without regard to betting limits, your bankroll will hit arbitrarily high positive and negative values. The expected value is still negative, but the variation is so high that it your bankroll won't stay either negative or positive.