How handy are you? You could build one from parts from Grainger. When my old one finally died, I bought a new pump and motor and rebuilt it myself. New, commercial units are industrial grade, and should last for 10's of thousands of screens. One caveat, you'll need to know a little about the proper nozzles and gallons per minute and motor size, but that stuff can be found, in fact, I'll bet Preston or Fred could lay that out for you. $100? you get what you pay for, most often anyway.
Steve