[Mister Ed]

The card and board games are separate things, even though they share many traits. (I should clarify that, when I say board game, I mean Munchkin Quest. There are Deluxe versions of the card game that come with a board, but it is only used for tracking levels.)

The card game is, I'm told, simpler to start with (I've never played the board game). To play the card game, you need to buy a Core Set. The booster packs, like Easter Eggs, are simply add ons to the base game. The Core Sets are the ones that come in a larger box and retail for $25 (at least in the US), or $30 for Deluxe versions (which include a board, and pawns, only for tracking levels).

EDIT: ninja'd, and by a better source of answers no less