Robot Books, Kits and other related resources and links
Scientifics Direct -- miscellaneous fun items.
American Science & Surplus -- miscellaneous fun items. sometimes they have the blinking lights to mount on buttons, but this is surplus so you never know what will be in stock!.
Dr. Don's Buttons -- button-making equipment & supplies, also can order ready-made custom buttons.
WebSticker -- custom sticker source.