My problem is that I know I'll probably only ever want to watch a given movie 'x' times. The cost to rent a movie is around $4, and the cost to buy a new movie

My problem is that I know I'll probably only ever want to watch a given movie 'x' times. The cost to rent a movie is around $4, and the cost to buy a new movie is around $30. For me, it's almost always the case that 30/x > 4.