If you want to save money and get a decent amp, look into the PPI Ion or Black Ice series. PPI makes some good quality budget amps. I have a 650.1 that will drive a 2 ohm load to 650-watts RMS clean and its only around $110.
Good amp brands: Sundown, AmericanBass, JL Audio, JBL, older Rockford Fosgate, SoundStream, certain PPI, DD, Kicker KX series.