A free game that I came across is Hexery. It is very similar to Magic the gathering and can be played for free at http://www.hexery.com

You get a 6 free decks when you join. It takes only a few seconds to learn and hours to master. As you complete achievements and duels you earn gold that is then used to buy booster packs to gain cards and build custom decks.

The duels are actually playable games and not like some of the other ccg’s I have seen, where you pick a deck then just watch. I like this game because it is customizable and I can actually play the game. The game is currently in is in open beta and a single player game that you will like.

Other features from their website is the fact that you can view other people inventories and trade your cards with theirs. The online market lets you sell off junk cards and buy the cards you need.

The graphics are a bit dated, and from posts on the forums they are temporary. I really enjoy this game so far and from what I can tell it is still new and the game staff is asking for people to test and report.

http://www.Hexery.com is where you will find your next tcg or ccg which ever you prefer to call it.