We ended up buying 3 photos. It was very expensive. It is kind of a hook...once you start doing it and collecting more photos on your account, it's hard to walk away from them. We had photos of our DS meeting Mickey for the first time so it was very precious.
I waited and waited for some coupon or deal or code but no such luck (for a small purchase like mine).
I will say one of the biggest plusses was that it was all of us and not just everybody else with mom behind the camera, as you said. We rarely have the gumption (or even think of it) to have somebody else take our photo of us all together.
You can try it, but be ready to get hooked. I thought the photos were really nice. They take quite a few shots so they can get at least 1 good one everywhere you go. Of course there are those poses where somebody had their eyes closed etc. but in all I thought they were very professional and well done.