I remember bits of the movie. 3 teens, 2 girls and a boy, go on a road trip. I think their truck broke down or something. Then some guy shows up and offers to help. So they ride with him and he ends up kidnapping them. The one girl woke up in a garage or shed with her hands tied behind her back. The guy was rapping, or going to rape the other girl. And the boy had these nails stuck through his hands.
I think the boy got away, and I don't know what happened to the one girl. But I know the other girl almost got away. She was driving one of his cars, but then he found her and shot her.

Sounds like Wolf Creek (2005) - IMDb (http://www.imdb.com/title/tt0416315/?ref_=sr_1), although I'm sure there's others with the same plot...