Amazon has the Back to the Future: 30th Anniversary Trilogy (Blu-ray + Digital HD) for $20 with free shipping for Prime members or on $25+. Has excellent Amazon Reviews.
Best Buy sells it for the same price.
Walmart has the Community: The Complete Series Pre-Order (Blu-ray) for $54 with free shipping. Amazon sells it for the same price.
This title will be released on September 10, 2018 from Walmart and on September 18, 2018 from Amazon.
eBay has the Fantastic Beasts and Where to Find Them Steelbook (4K Ultra HD + Blu-ray) for $13 with free shipping. Retail price: $16.