Zappo said:
I don't know how much a booster pack costs, I guess more than 5$ but less than 10$.
$3.15 'round these parts.
People covered the basics, but Magic is one of those (relatively) easy to learn difficult to master type deals. To be a successful player, people memorize at least the current sets (right now that's around 1000 cards or so) and know how the different cards interact with each other, which is often fairly complex.
If anyone knows programming, it operates on a FILO (First In Last Out - stack) system, which means that if I cast a spell, and then you respond with another one, the last spell cast occurs
first. This means when your opponent does something, you can do something to change play, then his spell might change how it works. Then he can do something in response changing it back so that when his spell resolves, it does what he intended in the first place. It can get very complicated.
The different colors represent different things.
Black - discard, suffering a disadvantage to gain an advantage, creatures with a price
Blue - Card draw, changing play, counter spelling, weak creatures, general control
Green - Big creatures, anti-artifact, quick land (for mana)
White - Lots of small creatures, flying
Red - Direct damage, quick creatures, land destruction, chaos
Colorless (artifacts) - all of the above, but more expensive
That's general, of course. There's more to it than that, but you build your deck around some win condition, some purpose. Like if I wanted to build a deck around keeping the other player from playing their own cards then decking them (making them draw their entire deck), I would go Black/Blue. Or if I wanted lots of little creatures with burn to destroy blockers, I might go White/Red. Depending on the block (the currently legal cards) these ideas might be better or worse.
It's a lot of fun, really. If you're good, you can play in tournaments and gain money. Tournaments are usually at card shops around the world on Fridays. And, when I say tournaments, I'm not talking about the big regional, national, and worldwide tournaments. I'm talking about 10 or so guys meeting at a cardshop with a $30 prize for whoever comes in first, $20 for second, and $10 for third. If you're good, you can just use that to fuel the hobby and not spend a dime of your own (except initial investment).