Actually, $50 is perfectly reasonable. Just because you do not like movies, does not mean many others do not find them entertaining.
A typical family will easily spend over $50 to see a movie in the theater, when you take into account concessions and ticket cost, parking. Double that if you need a baby sitter so that you and your spouse could go out to dinner and a movie. Quadruple that if it is a family movie and you want to take your kids.
So no, $50 is not unreasonable, especially you split the cost with friends.
This is also geared towards people who many not have gone to the movies to begin with and would have waited for the DVD or download to be released.
Me, I actually enjoy the theater experience, maybe I am just weird, who knows, but the last movie I took my toddler too (Deadpool.. just kidding), Minions Movie, and lets just say it was not a pleasant experience (at least it was for a birthday party and the theater was rented out for the group, so it was a ton of toddlers and everyone was understanding)