Re: Hiring Contractors - Are component/part prices typically higher than online?
Generally, a contractor has to order, pickup, stockpile, carry, sometimes return whatever they are getting for you. So they'll order it at the best price they can get, and generally sell it to you at full MSRP. Just like every auto repair shop you've ever been to. Or they may charge you the price the store charged them--but also the time they spent going to get it.
Of course contractors can be negotiable, like everyone else. the question is not what he's charging you for a gizmo, but what his overall cost to you will be. The guy who charges you $100 an hour may be cheaper than they guy who charges $75, but bills for 50% more hours.
Ask 'em up front, what's the total cost going to be. Some will tell you to feel free to supply your own parts--but they won't warranty your parts. If it doesn't work, that's your problem. Sometimes when they supply the parts, they'll also absorb any time replacing a DOA one, etc. Or ask for a price cap ("not to exceed") to the whole job.