Underwater with Kristen Stewart and the Star Wars movies are currently only ~$14 from several vendors including BB.
Don't know if it's any good, but I dropped by Wallies yesterday, and found a couple copies of The Color Out of Space with Nicholas Cage on Blu-ray in the $5 bin (after a bit of digging around). The price on their website is higher though.
The Biglots near me also still has BDs of The Shallows, and the unrated Hansel & Gretel: Witchhunters for the same price. They had some copies of Life as well for quite awhile, but those seem to be mostly gone. And they still have one or two copies of the lower budget, but decent alien invasion sequel flick Beyond Skyline for $3. And a number of copies of the third (or 4th?) Cloverfield movie, The Cloverfield Paradox (which I haven't seen, and therefore can't recommend), for $5.
I streamed a bit of The Shallows on the web, and decided I didn't need that in my BD collection. And have seen Hansel & Gretel a couple times. And as witchhunter movies go, I think it's probably a little better than the recent Vin Diesel flick. The violence in it is a bit over-the-top though. So I wouldn't suggest it for younger or less mature viewers.