Starting a casino can cost between a few thousand dollars up to a million dollars depending upon the specific configuration you require. Most companies entering the industry do not write their own software (this is strongly not recommended) but rather license it from a software developer. The software developer can sell a configuration customized to your own specific requirements.

Potential profit can vary ranging from a loss to millions. From the balance sheets that I've seen typical net margins are about 50% of gross revenue.

Refer to IGamebiz.com which provides consultation on setting up a casino.

2. Market a Casino through Affiliate Programs

Casino marketing is a relatively new industry. On the internet affiliate marketing programs are pay per performance programs that reward marketers for driving players to casinos. Typical affiliate marketers are web portals, individual webmasters and internet marketing specialists. However anybody can get into this game in a matter of minutes. Some of the top affiliate program providers are:

CasinoCoins
ReferBack

Refer to Affiliateaid.com which details the best affiliate programs available.
 

3. Become a Professional Gambler

Believe it or not there are people who gamble as a profession. These are people with very analytical minds. In my experience most professional gamblers tend to be poker players as they compete with other gamblers instead of competing against the house edge. Also note that it is very difficult to accomplish this.

My advice is to get into the business of selling advice to aspiring gamblers. Hundreds of gambling systems exist that tout guaranteed methods of making money from gambling. From my knowledge of gaming, there has never been a system that can overcome the house edge at a typical casino. However selling systems appears to be a better bet.

4. Professional Cheater, Hacker and Bonus Claimer

Some people actually earn a living through deceiving online casinos via computer hacking. There are cases of hackers changing the random number generator ensuring that all players win. Most commonly this activity involves stealing credit cards.

Others do this through ripping off casino via claiming startup bonuses offered as signup incentives. The problem with this is that casinos are implementing strict cashout policies that make this harder and harder to do. This also leads to increased restrictions on cashouts for legitimate players. A few countries are known as havens for this type of activity with Denmark leading the way.

We certainly do not encourage any of these activities as it causes new policies to be implemented that affect all players.