If you're talking actual re-wires or new wiring here's what I've spent a two different projects. Depending on square footage, a total re-wire with new panel (inside & out) runs anywhere from $8000 to $14,000.
Both of these projects were full-gut renovations of 100 year old homes.
The $6000 was a 1,400sf home, all new wiring, new interior and exterior panels, 200 amp service, permits pulled & rough-in through final including installation of all fixtures. Can lights were including in the bid, all other fixtures provided by owner.
The $14,000 was a 3,100sf home, all new wiring, 2 new interior panels, new exterior panels, new pole and upgrade to 200 amp service, lines for 3 HVAC units, permits pulled & rough-in through final including installation of all fixtures. Can lights were including in the bid, all other fixtures provided by owner.
If you're looking for strictly low voltage (audio, security, network, etc.), I don't bother for my flips, because there is no quantifiable return on on the investment. It has not hindered our sales in the $350K - $450K market. We've also found many buyers like to customize their own audio setups after they buy the house.