http://www.royalpurple.com/product/hp-2-c-2-cycle-motor-oil/ The STIHL synthetic oil that I've been using is about $25 for a 6-gallon mix which is a six pack of 2.6 ounce bottles; and that don't even include the gasoline! At the auto parts store, they have single quart size bottles of Royal Purple 2-cycle oil for $12.99. Now if 1 quart = 32 ounces; and I divide that by 2.6 -- that gives me 12.3076 or 12 gallons of gasoline mixed at 50:1 out of one single quart. Is that right ? ? ? Because if that's right, that's 1/2 the price of STIHL HP Ultra full synthetic.