A lot of this is going to depend on who does it and how much your willing to get involved. The blank panel will have to have the cutouts made and be powder coated and engraved. If you can remove yours for a few days and give it to some who knows CAD and has a cnc router you can just buy a $30 piece of aluminum and have it cut to your specifications. Expect around $300, I got off easy, all the coworker who cut it wanted was to go up for a flight. Then go find a local powder coated shop, expect around $50. Then if you want it laser engraved with the markings you may have to send it to someone if there is not anyone local. Expect another $50-75. The key here is that you are just using local fabricators and tradesman and not a avionics shop. Then of course you will need a mechanic to install it. Assumming your not moving a lot of stuff around and no rewiring is needed an A&P should be able to do this in less than half a day.
As for as the 930 I install my Jpi 900 under a friends supervision who is an IA. My opinion is that this isn't something that requires an avionics shop at $100+ hr as long as the IA is willing to read and follow the install manual. It's mostly connecting well labeled and color coded wires together.