almabrds: It depends on what you want to accomplish.
If you want to get legendary card back, for example, you don't need to spend money, there's lots of cheap decks you can copy (netdeck) in hearthpwn. One of the most hated, Face Hunter, can be used to go to rank 1, and it's very cheap. Unless you don't have patience/time to get gold, it's doable.
l0rdtr3k: And I already have to deal with 2 CCGs so I can't drop more money on another. 5 boosters per month is not cheap.
Perhaps I wasn't clear enough: you can get far in the game without spending money. Use the gold you receive every 3 wins, to buy packs (100g) or Arena (150g).
But maybe it's not a good idea to play another card game, because if you want to complete the collection in Hearthstone, you'll need to "sacrifice" a lot of hours to get the cards or a lot of money. Time/money that you're already using in Magic and Battle Scenes.
Hearthstone can be very expensive, if you want to get the cards now, without wasting hundreds of hours. I know, because I've spent more than $500 dollars already. But I want to make it clear that it's
not necessary, you can use rush decks in ranked mode.