When I had mine done, the most expensive part was the windshield itself. Cost 335, with taxes, here in Ontario most of that was the windshield. It cracked on me while I was out west and I was going to have it done in Seattle but couldn't afford it at the time, even though it was much cheaper like you have found.
Depending on where your truck is from and how well it was maintained there may be rust under the windshield that they need to repair so the new one doesn't leak. The shop I took mine to included that in the price, they had the truck for 4 hours (they informed me of this beforehand) but it only said "r & r windshield" on the invoice. It actually doesn't take them long to pull the glass, they had mine out in half an hour.
The place I took mine to was Apple Auto Glass. If the ones out there are anything like the one I went to I would strongly recommend them.