In Florida I use Pettit Trinidad SR (slime resistant), 70% cuprous oxide. $249.00 gallon. Two coats of primer and two coats of bottom paint. Warmer water really brings out the barnacles. I really don't think it's as much the cost of the paint, but how well it's prepped and applied. My boat's in the water 12 months a year. I guess it's different with a much shorter boating season.