National Lampoon's Barely Legal

Teenager Deacon works at a video shop, and his buddies, Fred and Matt, sell the bootleg porno films he acquires. Deacon gets fired, but the pals have the bright idea of filming their own Internet porn flick in order to make money and become more popular at school. Hijinks ensue as they cast and create their movie, but porn industry player Vic Ramalot grows jealous of their burgeoning success and tries to put a stop to the project.

They couldn't rent it, so they made it themselves.