You don't have to limit yourself to mono amps. There are 2 channels that you can bridge to 4 ohms to get the wattages you may need, but you'll need a svc 4 ohm or dvc 2 ohm sub. I have a pair of amps in the classifieds that would fit your budget.
I'll check there.
I think it's a great price, too. 1100w of powa for cheap. They be used in many difference configs. 4 chan for the fronts, and 2 chan for subs. Both can be used for a 3-way front.