www.lakesregiontennis.org
What do Meredith(6), Moultonborough(4), Center Harbor(2), Plymouth (4), and Ashland(2) all have? They all have public tennis courts that are free-to-use, and usually have an empty court available for you. Probably, it's the same in Laconia, Gilford, Alton, and Wolfeboro?
Waterville Valley has 18 red clay courts that get groomed and watered daily. For ten dollars plus $2/new balls; twelve dollars total; anyone with intermediate ability can show up on Mon-Tues-Wed-Thurs-Fri, weather permitting, at 9:30-am, and get into a doubles game from 9:30-11:30.
www.wvtennis.com. Smooth sole tennis sneakers are needed(!) for playing on clay.
Compared to many other sports like golf or skiing, tennis is an el cheapo sport to get into; for about twenty dollars you can get a decent Wal-Mart racquet and can of balls, and you are good to go, plus one can play tennis from age five to 95!