Everything was bought online for about $1100 I think. It's possible to power the front and rear speakers as well as the subs with one 5 channel amp, but you usually don't get much power to the subs this way unless you spend a bunch of money on the amp. Most people get two amps, one four channel for the front and rear speakers, and one two channel for the subs. Another option is to get two two channel amps, and power the rear speakers from the head unit. Rear speakers don't need as much volume and will provide enough rear fill from head unit power.