I would suggest stopping by some bikeshops and asking them what they have as leftover stock or used bikes. An entry level 2004 Specialized HardRock XC lists for USD $290 so I imagine that you might be able to find something a little lower if you dropped to closeout. Of course proper size and availability might be severely limited at this point. If you can up your budget another $50, you will have a wider selection to choose from. Just remember to buy only what fits.