Being a banker or a dealer of an online gambling site or casino, it will not ensure you any profit unless you owns the gambling site and many gambling addicts are gambling in your site or casino. A lot of gambling sites are now known for having their own uniqueness so if you will be owning one, better have a unique gambling site that gamblers will come back to everyday.
And just like the others said if you don't have enough money to start your own site you can invest it in casinos.
Let's be practical instead, just invest in gambling sites, there are a lot investment program now so we better take advantage on it.