I have 2 questions about the habitats:

1. What is the maximum level of a habitat?
2. How much does it cost to reach it(and if the price is very high, is it possible to reach it?)?

1. The highest level is 7 that holds 9 dragons.
2. The prices are variable, the more of each type you have, the higher the cost, whether they are on the islands or in storage. The first 2 levels are upgraded with gold, the next 5 upgrades are upgraded with tokens. And they are quite expensive and takes a lot of time to accomplish.