Like others said don't do it.
They will get you the worst materials that take the longest to install.
You will end up using your own materials or waisting a few hours for some screws, odd fittings, etc. The chances of getting all the right material is slim.
Then theirs the game of "find the material in the house". Different parts all over the house mixed in with other things. I would bet you will still end up unloading a lot of material off the truck. Then with a development you will have lots of stuff in one house and will have to cary it down the street to the next place. Then they will want you to warrenty their garbage.
If you want this then tell them to give you a job application. At least then you will have some rights.