Hunter H says:

if the 4 speakers are the right size for your doors it’ll be a couple of hundred since they gotta run new wires from the amp to each speaker and wires to hook up the amp and to install the speakers in the doors, if your car for instance had 5 1/2s in the doors or 4x6s then you’re going to have to pay more because some modification is going to have to be done to your car to get the speakers to fit