A few years ago, I bought a box of the CM6 spark plugs from Napa Auto Parts. As I recall there were 12 plugs to the box. Since I had to order them and wait a few days, the store sold them to me at a bulk price of around $3 each. I don't know what the current price is for these plugs, but it's worth a try to see if your local store will give you a bulk deal.