Prices of humidifier filters at Wal-Mart range between approximately $6 for a ProCare WF2 Humidifier Filter and $25 for Quietcare Console Humidifier Replacement Filter-HC-14. The cost of a humidifier filter varies mostly by the size of the humidifier.
At Target, prices range from approximately $6 for a Protec Replacement Wicking Filter to $13 for a two-pack of Vornado Evaporative Humidifier Wicking Filters.
Several stores sell humidifier filters, including Walgreens, Target, Wal-Mart and Amazon.com. Most stores sell filters that match humidifiers sold inside the store. It is easy to get total costs for a humidifier by pricing out the filters when considering the parent product.