Today only, October 12th and while supplies last, Home Depot has 4-Pack Arm & Hammer Air Filters for only $19.99 shipped! (Reg. $33.99) There are 16 different size options during this sale. So there should be the right size for you. This is a great price for these air filters. To give you a price comparison, these are selling for around $40 on Amazon. Grab yours now while they are in stock!