Building a cabin under $6000 possible?

[Palanakonu]

When time comes to add a bathroom, I thought about using this stuff for the roofing of it.
Have a friend in Ranchos with a few skylights made from this stuff... makes his place extremely hot at certain times of the day.

I heard they are prone to leak though because you have to screw them down in the "valley" instead of on the ridge "peak"... plus figured they would get brittle after a short time in the sun we have here.