Craigslist is a good avenue for finding old sails... if you want the material for crafts perhaps place an ad there that you will pay for shipping - people are always looking for ways to dispose of old sails (free) other than the landfill.
Sails are heavy, though, and shipping costs might get out of hand.
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)