Left to fend for himself after budget cuts, His tests cost over $500 a year to print, but this year he only got $316, one calculus teacher resorted to selling ads on quizzes and tests to cover his printing costs. $10 for quizzes, $20 for tests, and $30 for a final.

After a local newspaper featured his story, the offers rolled in and he sold out his semester. Most of the ads are positive messages bought by parents, while others are from local businesses.

While the story is cool, it does raise the concern that other schools and teachers might get inspired and start renting out space to more sophisticated clients, like McDonald's or Coke.

"The advertisers are paying for something, and it's access to kids," said Robert Weissman, managing director of Commercial Alert, a non-prof that c****ats commercialization in the classroom.