Schools is the best bet. Our schools love us... We donate all our smaller rolls to them. whether it's 10/20 FT of printable media, a couple yards of cut vinyl left, etc. We're usually nice and drop it off - We save all our smaller scraps, but also donate partial rolls. Everytime I get to the end of roll, 6-10 FT left... I just tape it onto a core, and usually theres a good 50-100 FT of misc materials for them to play with. Most of the time they're using it to cut on, not print, so theyre happy with anything we give them.
Or I play around with them. Practice doing multi color decals... I used some to learn how to do kiss cut, then perf cut... My bosses didn't even know it was possible. Long gone are the days I manually cut 300+ decals of different sizes that I just print and cut anyways!
We're going to have about 300 FT of 12" offcut 1080 blue. so I've been using it to wrap "everything"... Sometimes its good to keep for fun! My office has a ton of blue desk drawers now... We'll see how blue I can make it before someone notices.