all manufacturs do this, everytime a NEW atv is sold. its pretty much worked into the cost, you just dont know it. so yes its "free". the $100 goes to the instructor. thats how they get paid for putting on these courses.
as far as what it is. its super simple. they go over "how to stop" "how to turn" "decideding whether to go over or around an obsticle" "always wear a helmet"............
extreamly easy. nothing to be worried about. the PLUS is that they hold these classes at atv parks mostly, so you get to ride the park for free pretty much.