This looks good if he's got papers for the rebuild and minimal mods. Red is rare.
04 Subaru WRX
This one looks beautiful but a bit pricey, low miles too. It's owned by a kid so be especially careful.
2005 Subaru WRX Stock 40,000Miles
Basically keep an eye on craigslist and autotrader for a month or two to see what kind of prices to expect, so when you see a good deal you can jump on it. I would suggest going to look at a couple you know you WON'T buy so you get a feel for them and won't jump the gun buying the first one you see. And always buy as stock as possible.