Lowrider mountain bike??

I have been mountain biking for a long time, but recently got into lowrider bikes. My friend down the street has a really nice lowrider bike and he wants to build one for me. How much is a fair price? Can he use parts from my mountain bike to make it?
I already did some research at:
http://www.answerbag.com/c_view/233_faq/answered
lots of great info there. Should check it out!
So how much did everyone else pay?