You actually have to go where they make it. Cotton candy is made from colored flavored sugar that is spun out. If you want a light gray, they would mix the colors before spinning the cotton candy.
Also, ask around. If you only need a little, even the tabletop/home versions work - they just have low output. A facebook post might show up a friend who has one. People often get the tabletop machine as gifts for birthdays or Christmas.