Instead of offering the Crystal Ball as a separate item, the Sims team decided to pair it up with a set of hairstyles & outfits. If you have a spare 850 simpoints lying around, you can now grab the Crystal Ball, as a semi individual item. Check out The Soothsayers Crystal Ball Set.
Note that there are a few hairstyles that are not included in this set, which came with the originally released More Magic Set.
Thanks to 50/50 sims to the info!