Harbor Freight carpet cutter blades are on sale for $1.79 a pack. The stores don't seem to have any, at least my local one does not, and said they would not be getting them for several weeks. Online they are in stock at the same sale price. However, keep in mind that their cheapest shipping is via FedEx for $8.99. You will want to buy several packs at that cost. So I bought 10, for a total of $28+..so my blades are costing me $2.80 each instead of $5 in the LQS or fabric stores. Actually 2 blades in a pack, so $1.40 each blade.
Still a GREAT deal!!