In Munich we have hooligan clubs for the two opposing football clubs Bayern München and 1860 München: Schickaria and Cosa Nostra (now dissolved), both had stickers and always covered the whole city center with them, maybe more Bitcoin stickers should be distributed to the people who help.

Did you thought about adding stickers to downlaod to your library? 1000 Stickers around 100-200€ depends on the quality..