At Big Lots, I’ve seen them new for $3 or $4, and fairly recent movies too like “The Wrestler” and “Pineapple Express.”
I have 2 excellent independent stores nearby; one a few blocks away, and one a couple miles. They carry every obscure movie you could ever want. Plus, at the close one they know me and my kids and have biscuits for the dog. The kids get a lot more movies than we do, though. I use the library only if the stores don’t carry it.