Dont forget you get what you pay for. $800 to install front and rear gears in a ttb truck is not all that much, especially when you are taking it to somebody you trust....
I paid $300 for my rear gear setup with a rebuild on my factory limited slip. I paid $150 to have the front 4.10 gears setup into a D35 carreir that was already fitted with a used ARB and 4.56's. and out of the truck.
Whatyou are paying for is time, obviously the rear is a snap to access, but the front carreir in the truck on a TTB setup is not so simple, it takes time....
Besides you want to take it to a reputable shop who will do it right, these guys even washed and re-painted my diff cover for me, they also stand behind their work which is obvious because the passenger side axle seal was leaking and it is in the shop right now being fixed. After my 500 mile gear break in period I changed the fluid and spent $50 or so on Mobil one synth gear lube, they are refilling it with synthetic at no charge once they fix the axle seal.
Also they gave me a full diagnosis on the condition of my rear disc brakes, wheel bearings, and parking brake.
I would rather pay the few extra $$$ to have service like that then to have some shop say "tough luck, we're booked solid until next month, then charge me extra for synthetic fluid, and not care enough to tell me about and other problems they may find in there.......
So yes it is smart to shop around for the best price, but the best deal doesnt always come with the lowest price.....