We rented both canopy boats and pontoons in the last few visits and they were somewhere in the neighborhood of $35-40 for 30 minutes. We were a bit late getting back once with a canopy at POR, so decided to stay out an hour and they still only charged us for a half hour. You can go to DTD and back in half an hour. We went over on time because we went to OKW too, and sat and drifted a bit.
There is also a package deal or two if you think you will be renting quite a bit. We will probably do that next time as we really enjoyed it.