Basic accounts have a max of five pets. If you activate a Gold Account, you can create up to 10 pets. Gold accounts can then use the Mystical Montre Plushie and Mystical Donadak Plushie for extra slots to create up to 20 pets.

you can buy GA Medals from users shops.

and say when you active your GA and create 5 more pets, when your GA expires you can keep those pets you made :)

You'll need a [item2=1 month gold account medal].

Yes, it's a cash item, but as said, you can buy it from user shops as well. They're running about 8-9M right now.

Yes, you keep your five (extra) pets. Five of mine are from my GA.

Unfortunately those have inflated a lot in the last year. :|