You should also be able to find a Rotel RA870, RA980 or RA985 used in your price range. They are all 100 watts. I use a Cambridge A3i to drive a pair of B&W CDM-1 in a bedroom size home office system. The A3i was designed by Creek and is better than the A500. Will only cost you $250 used.
Most integrated amps are 50-60 watts and under. Creek makes some 85 watt amps, but they'll cost you $1k used. Many quality amps actually lab test out higher than the literature.