There are a couple different ticket types. You can get a ticket for one park or for both parks. When you buy the ticket for both parks, you can ride the train, in the Potter world, that runs between the two parks. Not certain of the cost, but should be online.
$124 plus 15 tax
Universal is cheaper the more days you visit. If you live in Florida I reccomend the annual pass.
I believe it is $100 plus tax
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