Walmart offers The Martian: Extended Edition on 4K Ultra HD Blu-ray Disc/ Blu-ray / Digital HD for $20.02 $19.52. Opt for in-store pickup to cut that to $13.11 $12.93. (For Prime members only, Amazon has it for the same with free shipping.) That's $5 under last July's mention and the lowest price we could find by $5.