3M Filtrete Allergen Defense Micro Particle Reduction HVAC Furnace Air Filter, 800 MPR (MERV 8), Pack of 3 Filters: $15.88 (40% savings); YMMV on sizes

For my house, I need 20x25x1 and found this good deal ( $5.29 per air filter; about 40% discount).
https://www.walmart.com/ip/Filtre…s/45649352
Regular price for a 4-pack through Walmart: $31.97 ( $7.99 per air filter); At stores, it is $8.88 per filter.
https://www.walmart.com/ip/Filtre…s/56052817
Available sizes:
12x24x1
14x20x1
14x24x1
14x30x1
16x20x1
18x24x1
20x20x1
20x25x1
I also need 12x12x1 but did not see a great deal.