We hired the most expensive boat, 30hp with electric start and a steering wheel, about two weeks ago, and it was €60 for 4 hrs, €90 for the full day. We hired for 4 hours and it was absolutely brilliant, easily got to Paleo with stops on the way. The guy is very helpful and you get all the kit plus a map showing how far you can go and emergency mobile numbers etc. You need to book in advance and leave €30 deposit, which is used to pay for the fuel when you get back. They accept all credit cards and the boats seem well looked after and reliable. Just do it, it's a complete hoot!!
Cheers
Sam