When you need more blades for it check out Amazon.com. I found a pack of 15 blades for around $90.00. That's about $6.00 a blade, not almost $20.00 each at most stores.
I used mine today to cut some plastic tiles, cut off an old lead sewer coller, remove constrution adhesive, and I had a 50 year old P trap nut that just would not come off. I cut it in half in about 2 min..