A good way to get a efficient card deck is to buy single cards in cardshops or @ ebay. But therefore you have to know the game and the different cards and strategies very well.
When you buy "Starter-" and "Booster-Packs" you have lots of unused cards and only a few really good cards that fit to your deck. So you have to buy more and more booster packs to get the necessary cards for a nice deck (that means spending more and more money). And of course you have to know some other people who have their own cards to play the game (or you need enough cards for several decks). You can also trade your unused cards for other cards with other players.
