I'm assuming you mean that you don't have any Magic cards yet, but would like to start collecting them to play the game. In that case, I'd actually, (despite my fondness of the Invasion block) recommend you go find a tournament pack from the recent Onslaught expansion. This will give you a fair amount of basic land (you need those to play) and a random assortment of cards from all five colors to begin your collection with. This alone likely won't enable you to build a good deck, but it's my own preferred method of starting out.
Another good option is to get a precon deck. There are fewer cards in them and it is consequently a bit cheaper, but these card packs are built to be able to play right out of the box. The same cards are packaged in them each time, which means you probably won't get any spectacular rares, but they are ready to go without any extra work. There are four for the Onslaught expansion:
Celestial Assault: an aggressive blue and white deck that focuses on harrying your enemy to death. Unique since blue and white aren't usually aggressive colors. One really good rare (Gustcloak Savior), and another rare I can't convince myself to like.
Bait and Switch: a trickster black and blue deck designed to allow you to steal your opponent's creatures. Of the four, it uses the hardest concepts and requires the most careful play style.
Devastation: a fairly straightforward red and green deck that focuses on big creatures...Beasts mostly. I believe Isimir, one of our other forum members started out with one of these, and it has seemed to work well for him as he has developed his collection from there.
Ivory Doom: a black and white deck that focuses on getting good and evil Clerics to work together to destroy their opposition. Its rares are fairly decent, and it wouldn't be a bad way to start out.
One more note for forum discussions...the one thing you'll have to understand to participate well is what the five colors of spells in Magic generally do well, since none of us will stop in the middle of a normal discussion to explain what we mean.
White is composed of the good guys...soldiers, angels, clerics, and lots of protection effects. Good for keeping stuff alive with a few high level attacks.
Blue is very sneaky and for many of us (including me) hard to get a handle on. Blue has lots of ways to prevent your opponents from accomplishing what they want to do and helping you to get things you want to do done. Its strong creatures are usually flyers...birds, air elementals, and such.
Green is big...the forces of natures. They have really huge creatures and ways to get lots of mana to cast them quickly. Its creatures are usually managed easily with nasty tricks and solid defenses, but if the tricks don't work for a little while, green can run over you quick.
Red is full of goblins and fire and volcanos and dragons and stuff. Lots of ways to deal out pain in the form of straight damage, but like green, little in the way of tricks.
Black is death. Zombies and ghosts and rats and crawly things. Black tries to get its enemies to wither to death, and has very effective ways to get rid of big scary green creatures. (and others like it) It can do almost anything you need it to, but often at a high price of your own life points. (If you run out of life you die)
Hope some of this has been useful ShadowHawk.
