What do you want the car for? Daily driver, weekend cruise, AX or track...? The 99 and earlier models all have a 2.5L engine, which is fun and fine for me, but may not be fitting for "Speedingbullitt". For the same money you may find a higher mile 'S' model with a 3.2L engine.
Prices are all over the place, and you may even save thousands by buying a car from a few hundred miles away. Look at the
classified section here and see some of the "Sold" deals.
Here's a quick way to see the asking prices in the Dallas market:
dallas cars & trucks "boxster" - craigslist