at my shop, we charge $55 labor for regular cdpalyers, $85-$120 for flipouts, double dins, navigations..... and $85 labor for running amp wires.... and that does not include wires, dash kit, harness, any parts..... and our labor has a lifetime warranty as long as the customer doesnt fuck with it....
but if its a GOOD friend, fuck it, make him buy you food and some beers and do the shit as a favor....