Poker can be played on many different sites, I found Pogo.com years ago and played on that site, all kinds of games from Dominoes, Chess, Cribbage, Solitaire and different Poker formats, The only problem is when you are playing for Fun People have a different attitude when they start to play for real money. So don't think that by playing fun money games you are going to kill it on the cash tables, Poker doesn't work that way.
Trying to learn Poker on Fun sites is all well and good and of course Risk-Free but until you invest real money you are not going to come up against really good Poker players, It is the same when you transition from Freerolls into buy-in Tournaments, You are going to come up against much better players, and the higher you take the game, the higher the buy-in, the better your opponents get.
That is why I always tell beginners don't look at Poker, as a way of making money, because you won't, Most of the time you are going to lose, so the better question is How much am I going to Lose? That is down to you and how much you are willing to lose, and how fast you learn the game.