I know I have found them at craft/fabric stores (large containers). I did a search and didn't really see any at michaels.com, but you could call them and ask if they have any in store. I would also check the dollar stores by you as I have seen them at some in the past.

Oriental Trading has a nice selection:
http://www.orientaltrading.com/ui/se...URI=searchMain

Hobby Lobby doesn't have any online, but I bet would have some in store. From their site, you can go to Crafts Etc (related company) which had some:
Search Craft Supplies | Crafts, Etc!

Hancock Fabric had some online, so they probably have some in store:
Craft, Cover & Repair Buttons

Joann.com had the following:

Large Cup of Craft Buttons-Assorted 16 oz

Bag of Buttons 4 oz - Many Styles

Colored Buttons-Over 150 Assorted

Ebay had a listing, and there may be more:

MIXED LOT OF BUTTONS FOR CRAFTS OR DECOR - 5.5 LBS. - eBay (item 360112862674 end time Dec-31-08 18:47:19 PST)

GRAB BAG FULL OF ASSORTED BUTTONS-SCRAPBOOKING & SEWING - eBay (item 270311494449 end time Dec-08-08 13:54:35 PST)

This craft supply has some listed:
Factory Direct Crafts

$18 for a 1lb bag here: 1 lb bag of assorted buttons: As cute as a button

More places:
Craft Buttons 1lb (400/bag) : S&S Worldwide

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