Are you looking for nice clean beaches to go to. We went to Wallis State Park  Beach in Rye NH very nice beach you pay $10 for parking, You get a bath house with showers and a snack shack.    http://www.nhparks.state.nh.us/ParksPages/Wallis/Wallis.html

Here somet other beaches in the area that are worth checking out:

Jennesse State Beach, North Beach,

http://www.nhstateparks.org/ParksPages/BeachesSeacoastHome.html