There are now 4 states that provide legal free real money online poker for real cash in the United States. Nevada, New Jersey and Pennsylvania. The laws are pretty much the same in each of these states, the exception is that in Nevada they only require the registration of a business as a credit card processor or an e-check vendor. This is not considered to be gambling, because you are playing for money and paying out actual cash, rather than playing for wagers.
If you want to play free poker online, you need to get your hands on some type of bankroll. Most of the time you can get a free initial bankroll from most any land-based casinos that allow you to play poker free for a certain amount of time (usually about 5 minutes). Then after the allotted time you have to either cash out or withdraw your funds. However the main thing when it comes to real money online poker is that you need to build up your bankroll. The longer you play, the more you will pay out, so the key is to start small and work your way up.
One of the problems with real money online poker is that there is no physical money involved; there is no physical bankroll, and thus no way to get your hands on a large amount of cash to try and bail you out if things go bad. Because of this, the best way to build your bankroll is through playing at online casinos using your credit card. This allows you to build up a playing account that you can then use to wager a few dollars here and there without taking out a loan, all from the comfort of your home. Also, since there are no debts to be paid back, you are able to avoid the risk of dealing with the pitfalls of gambling by avoiding the possibility of having to give a loan to yourself.