Tarpon Spring's Fred H Howard Park has excellent parking and launching facilities for kayakers and canoes. The gulf is normally pretty tranquil as it is, but the bay is even easier to enjoy. There's plenty to navigate around Tarpon Springs, and there are no entrance fees to the park or boat launch that I know of either.
There aren't any waves, particularly on the bayside at Fred H Howard Park, but the winds are gentle and constant. Parking and launching for windsurfing is easy and popular here. I don't recall any rental kiosk though.