I forget prices, but i’ll guestimate. Also, I generally used middle grade speakers/amps, the same things could cost more/less with different parts.
single 10" in a ported box with amp - 250-300
dual 10’s in a ported box with amp that ‘walled’ off the trunk. Looked like it was built into the car. When you folded down the back seats you saw the amp, looked like it came that way factory. - 700ish
This was the crazy one:
-same two tens in a ported tub that fit into the spare tire well - I made that, like 200 in materials and 24 hours of work
-They created a false floor to cover the tub that displayed the subs and two amps (one mono for subs, one 2 channel for front speakers) with ricer blue lights.
-Up front they put new speakers in the doors and tweeters in the pillars. Moved my deck down and install a flip out screen i got on ebay.
-The trunk lid got a 15" screen and two more speakers. When the trunk opened the speaker amp switched from powering the fronts to those.
-screens hooked up to a xbox, which i supplied.
All that for like 3000-3500. Most of that was labor, we reused the subs and one amp, I had the flip out screen and deck, I had the xbox.
All this was like 4-5 years ago, so prices might be a lil different now.