Walmart offers The Hitchhiker's Guide to the Galaxy on Blu-ray for $6.96. Opt for in-store pickup to dodge the $5.99 shipping fee. (Amazon charges the same with free shipping for Prime members only, although it's temporarily out of stock.) That's the lowest price we could find by a buck for this comedy sci-fi.

Update: It's no longer available for pickup at Walmart; however, Amazon still offers it for $6.96 with free shipping for Prime members.