Help from all you car audio geniuses(circuit breaker)?

Ok so my setup in my vehicle is eclipse deck, kicker components, 300 watt mono amp, 350 watt 4 channel amp, jl w3 subwoofer. The 4 channel amp stays on when i turn the car off and it kills my battery after time. However, the other amp turns off. Ive checked the remote wires and everything that could be causing it, so it is most likely an internal problem with the amplifier, which i dont want to pay to fix, so i was thinking of purchasing a circuit breaker and just flipping it when i leave my vehicle. I have a 4 gauge split into 8 gauge to both amplifiers. I looked at circuit breakers online and to my understanding most of them are based on watts? Im really not sure how powerful of a circuit breaker i should purchase for my setup. A guy from work told me i could go to home depot or lowes and get one from there but i dont know. The guy from audiotronics said a circuit breaker would die after so many uses. But i feel like i knew more than that guy anyhow.... Any knowledge on this would be appreciated. Thanks