Don't mean to high jack OP's post but I have a few questions.
We're going to WDW 2/20-2/27...we'll be at the parks 21st, 23rd & 25th. Do we pay for MM just once for the entire trip or do we have to pay for each day? I can't seem to find this answer anywhere
First off for me, I've never been to WDW or DL.
With that being said. Memory maker for me it totally worth the money. Regular price is $199; advance purchase (3 or more days in advance of your trip) is $169.
The amount is for your entire trip. Each photo costs upwards of $10-15; 17 photos and its paid for itself.
I will always pay in advance for this. My first trip is just me and soon to be hubby. The next one planned is for my oldest daughter and 2 grandboys.
I lose things very easily - phone, blue tooth, car keys, bank card... you name it if I don't put it back exactly where it belongs its gone forever.

So the MM for me means not having to take my phone out to get a picture of us and then having to remember to put it back LOL.
It also means I can be a photo hog - which I love to be. You can download all the original photos and then go back to the MM website and play with their editing options... you can add words borders fireworks etc. You can ask each photographer for magic shots (ones with characters), plus all the ride photos and videos, plus any that are included with meals.
One other thing... if you don't want to pay for the MM package as a whole... ask around for a Memory Maker share for the time frame you are going.
Pro - its cheaper to get all the photos you want.
Con - you have to surf through ALL the other photos of families that shared as well.
Hope this helps!