We did it about four years ago, and for our family of four I think it was about $5 a day? We used this service for the three days we were there, so I'd say about $15k? (We did the WHOLE day, so we never had to wait for anything and visited all the parks with them, had rsvps at restaurants made for us, things waiting that we requested, etc). We also toured their other resorts, and if we needed something from a shop one of the guides would get it for us so we could just focus on the attractions and characters, and the kids got a private tour of things like meeting all the Disney princesses in the castle without other people around rushing them along or getting into our pictures. I think I remember providing them with the list of our asks, and they returned with an itinerary for us to approve that included everything, and some suggestions for things we weren't even aware were options.