In all likelyhood...it's the front that's tucked, i.e. the forks and likely the steering head is bent inward toward the frame.
Yes, it can be fixxed..but the frame needs to measured, and possibly the forks need to straightened, or replaced...niether of which are cheap...There are places like www.gmdcomputrack.com that specializes in doing that sort of work.
If your lookin to buy a bike that may have the above condition, you need to pay VERY little for the bike, or find another bike to buy.
if the frame is straight, but the forks are bent, check on ebay for prices of used but good forks. Depending on what bike its for, they usually go between 100-300 for the forks and maybe another 50-150 for the triple tree.
If your not mechanically inclined, then buy a bike thats not wrecked. I'd also stay away from bikes with bent frames as most new bikes are aluminum and having cracks in that is very serious.
you got pics and what year is it? also what you could do is buy a new frame and put everyting in it. But the cost and time to do that is a lot of work. Unless your gettin a new bike wrecked for that cheap, it wouldn't seem worth it. Frames go for atleast 500 bucks, subframes are around 300ish.