Since nobody posted much info, here's what I have found on their website.
Daily Rentals
$120 half day (4 hours)
$160 full day (4+ hours)
+ $5.00 per person to enter/use the county park.
Rental includes everything you need to enjoy a day meandering the Rainbow River:
Seating for up to 4 adults and 3 small children
Electric Motor
Acrylic Viewing Panel in Hull
Swim Platform
Safety Flotation Devices
Home Page - Florida Glass Bottom Boats
Rent A Boat - Florida Glass Bottom Boats
Rainbow River & Park Hours
The Rainbow River and the launch site we use, KP Hole Park, are managed by Marion County Parks and Recreation Department.
Summer: 8 a.m. – 8 p.m.
Winter: 8 a.m. – 5 p.m.
Entrance fee: $5/person