You'll need various dice, and some sort of figures to represent your characters would be ideal but honestly you could use anything to represent them. You'll each need to print out character sheets, you can find them easily on line. It would be smart of you to buy the manuals (monster manual, dm guide, player's handbook etc). You'll need a dungeon master, obviously, to create the world and quests. And honestly i wouldnt freak out about the rules. When I play we do a lot of improvisation based on what seems fair, its a better system then sticking closely to the rules. Remember, this is a paper and pencil rpg, not a video game, so technically whatever you guys say goes.
Have fun!