alternators are expensive.

Get a good one so you won't have to do it again.

Unfortunately I'm a chick. which isn't so bad, but I'm one with almost no car knowledge, so I give you what I remember from when the alternator on my parents' blazer went out a couple of years ago:

it sucked.

Go to O'reily's or autozone. I'm sure they know more than me. that's where dad got his anyways.