Don't buy an SC if you are looking for reliable transportation you will not find it here. If you are going to be on a tight budget then buy a car you know you can work on yourself and doesn't cost a mint for parts, and has readily available parts.
Headgaskets blow on bone stock cars as often as they blow on modded cars, just look in the classified section of this board.
If you have your heart set on an SC buy one from an old lady that has all the maint records from the time it was new, has only 40K on the Odo., and has been garage kept all it's life. Other than that you will end up on foot.
Jeff