I recall there was a $2 shipping charge for each sticker. There is probably different shipping prices for each lot.
Now if I would actually put it on my car I don't know, but for a couple of bucks it's funny to have.
It is still odd. If a single bumper sticker is $3 plus $2 shipping, 5 should be $15 plus $2 shipping. Sending a bumper sticker or 5 bumper stickers should only require one $.37 postage stamp.