i think i remember seeing them on weedcity.com like standard dime sacks 100 for 10 bucks or so. or i have heard of people getting them at fabric and craft stores, because they use them for buttons and such and usually have a shit ton of them that they will give you for a few bucks
Weedcity is wonderful.....anything and everything a stoner could ever want or need, aside from actual weed, of course.