We had good luck at the Guest Relations place inside Epcot in June 2015. Of course, our tickets were part of a Disney package, so that might have helped.
In Feb 2016, I "bridged" my annual pass purchased in June to the new annual pass so I could get memory maker for about $100 for that trip and our next June trip.
I did as others have said and figured out what the price should be ahead of time, and the CM did it correctly.