Last year I bought 3 gal Zerex G-05 & 3 gallons distilled water......(it takes 3 gallons of 50/50 for each car) that was 6 gallons of mix......one for Fred & one for Wilma.....local shop charged $15 or $20 labor / car. I did the mixing myself before taking it in to be sure we ended with a 50/50 for each.