I always launch at the Meredith Public Launch. If you get out early in the morning, it's free. If you launch later and on weekends, someone is there to take 10 bucks to launch. The parking for the launch is behind an Ace Hardware store just north past the first signal light and it's free too.
That list is a little out of date. Ames Farm in Gilford is no longer an option to launch unless you're staying overnight in one of their cabins from what I hear.
Cal