I generally stock up on sprinkles when they go on sale at the stores. I dont use them very often but I I try to buy a couple during each holiday season, hearts during valentines, leaves during fall season just so if I need some I got some. If I buy sprinkles online I get them at sugarcraft. Only really bought white from them so far.
We have a local store here in northeast PA that sells bulk food and I always get my sprinkles from them. They do have a website – www.bulkfood.net
Though this is for the BIG bags of sprinkles. They have shaped ones and jimmies and all kinds :) Hope this helps!