I'm planning on giving my kids a set amount of money for whatever they want, I'm planning about $100-$150. If they want the wand they can use their money to purchase it!
I would want my own. It just depends on how much the kids are into it. They'll have to take turns to do spells anyway as long as you are all walking around together. It is one person at a time. If they are very into Harry Potter I'd get them each their own. If they're not that big of fans maybe buy one so long as they can share.
I think the hardest would be getting them all to agree on one style. They have all the different character wands and they're all so elaborate. With the big deal HP makes about the wand picking the wizard I think everyone would want a different wand.
We shared...never any issue. Kids understood they were expensive and didn't see a need to each have their own. Funny enough, our 2nd trip, I forgot the 1st bought wand, so we now have 2 from 2 trips...hopefully our 3rd trip, we remember both...
My son and I shared *his* wand and if I were an impatient child, it would have been very difficult! I enjoyed the wand experience more than expected - might have to get my own the next time we visit Universal
The kids I've noticed sharing a wand seem to accept that mom/dad picked up a wand and that's the wand they are using. Not all families work like that.
And then on the other side, I saw identical triplet girls each with their own wands. They were, like, 2 years old, and had NO idea what they were doing, but that was OK because the wands weren't interactive but they were playing at the interactive spots.
My kids were 7 and 5 when we went for the first time and they shared one for that trip. On the next trip we bought another, so spread the cost over 2 trips. It worked fine for our family, but my kids know I'm cheap so I think they were surprised to be granted one to begin with.