I steal stickers off watermelons in the fruit bin at the grocery store. Whew. I said it out loud. I am a thief. Actually, it's funny - the one pictured on the cover of my Sticker Book is actually a vintage one I paid for on ebay. I guess I'm not a total thief!
I always try to find a label that has adhered itself to the side of the cardboard bin. And sometimes I find a watermelon that has two stickers on it.