Movies tend to my go-to comparison. How does <product X> compare to an evening at the movies with popcorn and a drink. Which is like $15-20 for a couple hours.
Seems like you should have to add the beer and munchies into your D&D session cost if you're forking over the dough for movie popcorn and soda. ($1.50 an hour more then? So it's still cheaper.)