Like I suggest you buy the one with the nicest buttons and then once you get it paint on the other! (so if you had cherries, paint on extra bubbles), (if you had bubbles, paint on extra cherries!)
Hope u find this helpful!
PAINT:
I'd go with acrylic and a very FINE brush - also a circular stencil so you don't go out of line.
While you're at it, you might want to add keychain charms, stickers, change the background and swap buttons - add name charms and invent wacky paint-sayings.