Home Depot offers the NaturalAire Standard Pleated Air Filter 12-Pack in seven sizes (16" x 25" pictured) for $20.12 with free shipping. That's $1.68 per filter and the lowest total price we could find by $26. This filter is 1" thick and has a performance level of MERV 8.

Home Depot also offers the NaturalAire Best FPR 8 Pleated Air Filter 12-Pack in in seven sizes for $59.82 with free shipping. That's $4.99 per filter, $60 off and the lowest total price we could find. This filter is 1" thick, electrostatically charged, and has a performance level of MERV 11.