We just got home from Sallem Willows Beach, park and boardwalk. What a fun day! The beach is small and has lots of shells and seaweed, so the sand isn't smooth and white, but it's clean and welcoming and free and open to the public. Parking is just feet away from the sand. The park is beautiful and the lovely boats in the harbor are nice to look at. The boardwalk is just like the old fashioned boardwalks I remember as a kid, with an arcade, the ten cent fortune teller machine and several baby and kid-sized rides, including a nice carousel.  I was worried about finding the place, but it was really easy. See the website for directions and a map. Oh, they have concerts at night in the summer too.