that all depends on how much you have to do to get it where its got to be. whats your hourly rate, whats the material cost, what's it worth to you to climb into that attic, thru the insulation and pull the wire. then you've got to get it down the wall (fishing, two people) and into a box (whew) before you install a device, cover plate and breaker. then your markup. i look for about 50 to 65 bucks an opening for new work (rough) no devices, no fixtures. 100 bucks minimum for old work/per box if it's a whole house or partial rewire. if it's a sinle run, minimum trip charge *(whatever that may be for you) plus your hourly rate, plus materials, plus markup