Low budget cheesy teenage movies where the norm back then (Dude wheres my car, she's all that, american pie, varisty blues, 10 things i hate about you, i know what you did last summer, american beauty, jawbreaker, bring it on). You could make a shitty low budget movie aimed at junior high and highschool kids and make 4-5x the budget easily. Combination of the budget for the movies being low + it seemed like back then any movie regardless of if it was good or not would get at least 40 million at the box office.
It got so bad that they actually made a movie called "not another teen movie" which was a spoof of like 30 different shitty teen movies from that era