New England Fabrics in Keene is the only one I can think of in NH. If you're wiling to travel a bit try Fabric Place Basement in Natick Ma, or SewFisticated in Somerviille, Framingham, and other places. Neither of these two are
difficult to get to, although I'd call and explain just what you're looking for.
You might also try Walmart if yours has a fabric section. It was my go-to place when I was working with knits. Beautiful thick cotton knits for $1-2! Not that long ago. Good luck.