Walmart offers Batman: Under the Red Hood on Blu-ray for $6.83. To drop the price to $6.76, opt for in-store pickup. (Amazon has it for the same.) That's the lowest price we could find by $8.

Also available is Superman: Doomsday on Blu-ray for $6.83. To cut the price to $6.67, choose in-store pickup. That's the lowest price we could find by $4.