The state launch (lakefront) charges 5$ /per launch. There are attendants from 4 am - 8 pm daily.
They say that this is to keep the zebra mussles out of the lake.
They will be glad to sell you the passes. I launched appx 20 times last year and did not have to get the boat and trailer steam cleaned once. ps can't understand how they can pay 4 attendants 10/hr when they only get 25 - 35$ a day in launch fees.