Magic the Gathering, Pokemon, YuGiOh are all theoretically expensive to keep at. It is possible to buy a starter set, but because these have a history and tournaments and 1000+ collectible cards involved and variations of rules and rule interpretations, it's messy.

The upside of that type of game (TCG,trading card games) is they have tournaments, places to play, people to play with, and offer the novelty (and additional statistical/strategic challenge) of designing your own deck to play with.