The Sims 3 Store team has really boinked up the Store Sets and premium items this year. Multiple sets with half of the objects in one, half a set in another…it’s really a mess. 😛
Anyway, for those of you looking to grab the Crystal Ball separately, can do so in game. Head into Buy Mode > Electronics, and the Crystal Ball is available separately for 600 Simpoints. I have no idea how long it will last in game, so if you want just the Crystal Ball, grab it soon!