Hi Sharon,
I'm so glad you stopped by for some clarification with your great question.
Disney's PhotoPass is a service offered at Disney Parks.
Memory Maker is a product of that service which includes unlimited digital images for 30 days beginning from the date of the first photo. These photos are taken by either Disney PhotoPass photographers throughout the theme parks and from select dining locations and attractions. There is a set price for this product and there is even an opportunity to pre-purchase it for a discounted price.
You can still use Disney PhotoPass without purchasing the Memory Maker product. Disney PhotoPass photographers are at numerous locations throughout the parks and some resorts. You are not obligated to purchase and you can purchase as few or as many photos as you like upon return from your vacation or you can even purchase photo prints at select Disney PhotoPass sales centers during your trip. There is also an option to purchase individual digital downloads without the purchase of the Memory Maker. So, depending on how much you might utilize this service will help you determine whether the Memory Maker is worth it for your family's travel budget.
Personally, I love using Disney PhotoPass and because I have purchased so many individual images in the past, both prints and digital images, the Memory Maker is worth the expense for my family. I hope this helped clarify this for you.
Have a magical vacation and say "cheese!"
~Allison L