look at their website then, theres a ton in MA. but no promises, building 19 is usually filled with random shit and i think i found it there this time least year, so its a long shot. but really cheap, like $25 for a 30x6 foot roll
you might want to try to use a tarp i tried it last night and it worked pretty well. just do the same only secure the top withy some screw drivers or sticks and then water it.