Is this a good deal on subwoofers/amp?

That's not a bad price for a combo. Just know that you don't get the warranty b/c they aren't an authorized dealer. The amp is 1000w peak, but it's 500wrms @ 2 ohms, which is what the subs will be wired to, so each sub will get 250wrms. It's not a bad setup. Get yourself a ported box if you want it to be boomy and a sealed box if you want it to sound tight. Good luck!