There are plenty of AMPs available in the US available for well below your max budget, AB, AB hybrids, G, H, and Class D.
You definitely want to make sure that your amp has failed and not another component or speaker so you can appropriate money correctly. If all 3 channels developed the same problem at the same time then you can most likely rule out you speakers (I'm not sure clipping would be the characteristic but let's see). Since surrounds don't pull much power at all, and just confirm so you can rule them out by running them as mains.
What are you currently driving your left and right speakers with, and what speakers are they?
Edit: what do you have the center speaker crossed over at?