Crown Com-Techs, Micro-techs, and the like
These can frequently be had on E-bay for around the $100-$200 range. Last year, when Tower music shops closed up, they sort of flooded E-bay with a ton of Com-tech 800 amplifiers, which all the stores had for their in-store sound systems. They are 400 watts RMS per channel, or 800 bridged...sort of like what you are looking for...I bought two from the local tower music for $100 each and use them on my home theater system. There are lots more to be had around the same price. Com-tech amplifiers have screw terminals for the audio ins and the speaker outs.
There are other amps built in the same design under the names "macro Tech", Micro tech", and "Power base" all of these design amps are extremely durable amplifiers that sound great!