Might i suggest looking into Fantasy Flight Games's LCG's? Living Card Games.
Especially this one, the new Warhammer: Invasion LCG:
Fantasy Flight Games [Warhammer: Invasion The Card Game] - Leading publisher of board, card, and roleplaying games.: Invasion The Card Game

Every month 40card sets come out. Occassionally a small larger expansion.
Base set comes out in oktober i believe. Every month a small deck of 40 cards. In a few months there will be a larger expansion that adds some more rules. But overall you just have a monthly investment of well... not much. It's a cardgame you can collect all cards from without going bankrupt.
Rules are up too for a proofread.

For the rest they also have the LCG of a Game of Thrones and that of Call of Ctuhullu.
Previously both CCG's that switched to LCG systems:
Fantasy Flight Games [Catalog Living Card Games] - Leading publisher of board, card, and roleplaying games.

I can strongly advice you to take a peek.

^___^ I am hoping to start a little discussion on this game and the other 2 LCGs. As the format and settings deserve it. And the execution of FFG's cardgames so far is quite good.