Free: Contests & Raffles.
Here is my advice for what it's worth. I never treat for mites with anything but powdered sugar. My hive setup is a bit unorthodox as I have all top bar hives. The bees do have mites but with powdered sugar treatments about three times a year they drop a bunch and seem to manage the rest just fine on their own. Just FYI I've got eight healthy hives.