Welcome to Subeta! There is a Collaboration Sticking board under the Achievements section of the forums which have a bunch of people who are happy to help stick stickers, probably a good place to look for sticker buddies! Alternatively, the Hustler at Pina Park also sticks stickers for you for a fee (it does give you odds of getting Hustler only stickers too!)

Useful Links:

What to do on Subeta? FAQ Useful general information for newbies Finding friends (Chit Chat) SubetaLodge (Offsite item database, pet colours etc.)