The Aprilaire 760 humidifier uses Aprilaire 35 Water Panel Humidifier Filter Pads. These can be purchased from a number of online retailers as of February 2015, including Sears Parts Direct, Amazon.com, Filters Fast LLC and Appliance Factory Parts.
At Filters Fast, filters for the Aprilaire 760 can be purchased either singularly or in groups at reduced prices. As of 2015, a single filter costs between $10 and $17. Buying four or more at a time puts the cost at the equivalent of about $8 to $12 for each. Further price reduction can be obtained by using the company's auto-delivery option.
The filters at Sears, Amazon.com and Appliance Factory Parts can be bought for around $5 to $10.