We just got back from WLV and they had boat rentals there. We thought about it, but it was sort of expensive (in my mind). I believe the rates are the same throughout the resorts. I remember the 2 seater WaterMouse boats - they were about $18/half-hour and $36 for an hour.
If I remember correctly, I believe they also have pedal boats at OKW, though I don't remember the rental rates on them.