I have never purchased blades on EBay but am interested if they are less expensive. I have bought them on www.Connectingthreads.com at a reasonable price. I was told that if you use your rotary cutter to move the cut fabric away from the piece your cutting it from, IE: accross the cutting matt that it will dull your blades quickly. I really don't go through blades too often but I never use them to cut anything but fabric. I do keep old blades to cut freezer paper sometimes. Hope this was helpful.