People who race boats go through more plugs than sport fliers, so we won't tolerate being overcharged. You can get McCoy MC-59s for $3.50 from: http://rocketcityracing.com/product_...23&item_id=994 . The last time I bought plugs, about 10 dozen McCoy MC-9 and a couple dozen MC-59s, I paid about $2 each.