I use my set-top digital box to order pay-per-view movies often. I generally order at least one a weekend.
It does cost more than renting one from a rental machine, but I live way out in the country, and the gas I save by staying home and renting a movie makes up for it. Also, I just don't want to leave the house.
On weekends, all I want to do is settle down on the couch with my popcorn, chocolate, and soda and enjoy a movie in the comfort of my home. I love the rental feature of my set-top box, and I think that the experience is worth a few extra dollars.