The main problem with casino bonuses is that they are often not real, but are just a way to get you to start playing the game. In short, the bonuses cannot be claimed as cash. Going even a step further, the bonuses cannot even be used, sometimes, to win cash. If you make a lot of money using the bonus money that you were given to start, you cannot then go claim your winnings. These are still valuable because they allow you to play the game for a while without any risk, but they are not as valuable as bonuses that you can use to make money. Most places, of course, will not let you claim the bonus money itself. You will have to write that off. However, the good casinos will allow you to collect the winnings that you got from your bonuses.
In order to find these, it is very important to look at the fine print. Many places will offer bonuses if you decide to come play at their venue, but then will not allow you to claim the money. You will want to look very carefully at the fine print to see if the money can actually be kept, or if it has to be given back. The headlines alone may state that you get large amounts of money, though these can be deceiving. The larger the amount of money that is being offered, the more careful you should be.
One company that gives out real bonuses is Bodog. Another is the Lucky Red Casino. These places will actually allow you to play with the bonus money and make real gains. This is a huge advantage to a gambler, since it cuts down on the risk that you will lose anything, and allows you to lose more before it becomes a lost cause. There are other sites as well, but these are two of the best because they are major companies with many clients who are all very satisfied by the way the bonus system works.