Hi Kristina,
You can purchase your
MagicBands before you visit the parks. If you are flying in to Orlando International Airport you can purchase
MagicBands at The Magic of Disney or Disney's Earport. If you are driving to Walt Disney World, you can purchase
MagicBands at Walt Disney World Resort Hotels or Downtown Disney.
If you haven't set up accounts on
My Disney Experience, I highly recommend doing that before you arrive. You can link your tickets and make
FastPass+ selections. Then when you purchase
MagicBands you will only have to link the bands to your accounts!
Please let me know if I can help you with any other questions!
Wishing you a magical vacation,
Amy H.