Horsn are gaenerally very efficient and you can use a low power amp and get very high volume levels. Some folks with horns even use tube amps that put out 10 wpc or less. Would need to know the efficency of the horns. You might run a search for other threads on low power ss amp. Pass Labs 30 is one that comes to mind, but would cost you more than what you want to pay. One v. good ss amp that is only a little more than your budget is McCormack DNA 0.5 which is 100 wpc and would cost you about $6-700.00.
Amp suggestions
I have a pair of Klipsch kg3.5's. I have had an adcom 5400 on them at one point. I have $400-500 to spend on an amp. I was going to get an adcom 555, but I'm finding out that may be too much power for the speakers I have. I had a tube amp suggested to me, but I'm not sure I can go that route. I'm using my yamaha receiver as the "preamp". I really like volume, I usually listen to alternative/hard rock. So I'm not sure I can get a tube amp that would be loud enough for my price range. Aslo, how would a tube amp blend with the other 3 speaker while watching movies? Are there any other ss amps out there that someone might suggest other than the adcoms? Ones that might not have quite so much power, but would sound better on the horns. Thanks for the help.