MTG can be extremely expensive. But if you are only playing casual as another poster suggested, why not build some decks with proxies?
Get some sleeves for your deck and put the common cards in. Print out the rare cards you need on some thin but HQ paper (some people write with black sharpies all over cards what the proxy is and it looks disgusting. plus it helps to have the real card reference) and test it out with your opponents. You can tweak the deck to how you like it, and then if you find a pile of cash, you can buy the proxies that you want for real.
I did just that perfecting my mono red elementals deck... but I'm hard pressed to shell out $200+ replacing my Mutavaults with real cards. Since I'm not competing in tournaments, who cares? I was also able to replicate a Kithkin white aggro and Fae deck just to see what it's like playing with them, since they are still very strong on the pro circuit. Of course, using those super powered decks against my buddies isn't very sportsmenlike so I defer to other decks... although a friend of mine likes dueling me against those power decks to make sure his deck built with commons/uncommons can stand up to it.
The beauty of MTG as opposed to other CCG's is that, yes, even though expensive cards are powerful, it's ultimately the LUCK OF THE DRAW and the PLAYER'S CHOICES that determine the outcome. It should never be one sided. The first time I drafted (with Morningtide/Lorwyn) I actually defeated my opponent who is a waaay better player than me because I had Incendiary Command and he blew his hand placing a bunch on weenies on the board. After that I realized expensive cards and experience only count for part of the game. And that's a plus.
Proxies: I practiced it a lot and perfected my technique. With the right paper and cutting I had a couple of buddies fooled for a minute over a Black Lotus I created.

But they don't have to look perfect... just enough for you to build the right deck at no cost. Standard and type II decks can cost a fortune. You can blow up to $500 on your mana base alone.
BTW, a couple of my friends found playing with SINGLE BOOSTERS quite a lot of fun. You have some land nearby (you'll need 2-3 of each basic land at least) one each player opens just ONE pack, apply the lands as needed and go at it using only the cards from your booster. You end up playing cards you never thought you'd like... it's cheap and fun and generally the games aren't too fast so you can cast stuff that's normally difficult to resolve. Give it a try.
Bought some stuff from Zendikar today, along with some mixed cards from various sets. My local comic place runs some nice deals on those. Now I'll have to see how it works with my existing collection.
Did you get a Lotus Cobra??
