Hi, Julie! Thanks for bringing your question to the Disney Parks Moms Panel.
You are more than welcome to purchase 
Memory Maker for a friend prior to their 
Walt Disney World Resort vacation! There are two ways you can do this. This first is to purchase the Memory Maker via your own 
My Disney Experience account and then 
reassign it to your friend. You will need to make sure you are connected to each other in your 
Family & Friends list, though, in order to use this option. Simply locate your Memory Maker under the “My Reservations” section of your My Disney Experience account and select the “Reassign” link.
You could also purchase a Disney Gift Card for your friend and then include a note indicating that it’s intended for use in purchasing Memory Maker. Disney Gift Cards are offered at a variety of big box retailers and grocery stores throughout the U.S., or you can purchase them online at 
disneygiftcard.com.
Either way, make sure to purchase the Memory Maker at least three days prior to your friend’s arrival at Walt Disney World Resort in order to take advantage of the advance purchase discount.
Please let us know if there’s anything else we can do to help you spread some Pixie Dust, Julie! Have a Magical day.
Amy