You are going to spend well over $2k if you go this route...
Maybe start with a smaller setup that costs around $1500-$2000 then upgrade to better equipment and more electrical after you get used to the first system.
With the sub and amps being recommend that will be about $1200-$1500 right there. Then you have $500 for a H/O alt and another $500-$1000 in batteries depending on which brand you go with. Then factor in another $300-$500 for wire, building material, sound deadener, etc. Then you will want better speakers, an amp for those, and a new deck. There is another $500-$1000. It all adds up quick when you want to run 3-5k watts...