At which Level does the Water Park unlock?
The Water Park unlocks once you reach Level 80.
What are Aqua Coins?
How can I obtain Cards while playing in the Water Park?
It's not possible to obtain Cards in the Water Park since all the available Cards have already been unlocked for you.
Why are Cards in the Water Park so expensive?
Cards are more expensive to place and upgrade because they are all unlocked from the get-go, therefore you do not need to find them to place them. To ensure a better experience, their price are more expensive in exchange.