How do you get a pet on Wizard101

There are many ways to earn and/or buy pets.
You may purchase one from the shopping district in Wizard City (or most other worlds but you must pay), get a pet drop from a boss (Nightshade is a good idea), or earn one from your quests (at level 7 you earn a piggle).

You may also buy crowns and select a pet from the crown shop. Hope this helped, good luck!