There are lots of saws that show up on CL, most common type is a contractor saw that has the motor hanging out the back and the trunnions (the parts that mount the arbor and blade and allow it to pivot) are mounted to the underside of the saws top. The problem with most of these saws, especially if they are older is that the fences are usually pretty crappy. My old sears contractor had a fence with rails that were essentially just pieces of angle iron. Newer saws either have some sort of aluminum extrusion or a tubular box that aligns the front of the fence at 90 degrees.
The smaller jobsite saws are generally a step or two below the contractor saws with screaming universal motors and crappy fences. An exception might be the Ryobi BT saws, they seem to have a better fence and a sliding table though they still have those screaming motors.
Depending on where you live, you should be able to find something used on CL. Just take your time and give each candidate a good lookover before you plunk down the cash. Look for a newer fence and check it for accuracy.
If you want to spend a bit more, Griz has a contractor saw with a decent fence and a true riving knife for 750 shipped. I usually recommend older American iron, but Griz stands by their products and generally offers good value for the dollar.
http://www.grizzly.com/products/Contractor-Style-Saw/G0732