You should be able to pickup a clean 9-3 for around $2k if you look for a good deal, then sell for $4k.
I paid $2000 for mine then wheels, front mount, cold air, and springs/shocks.
Parts are easy to find, you just have a limited number of aftermarket brands.
I love mine and the hatch makes it easy to haul a lot of stuff in the back. If you maintain them, you will be able to put another 100k miles on that car.