There is a known issue where some players see a lower price in the Summer Offers calendar than the actual price. However, the correct price is shown in Apple's purchase confirmation pop-up prior to purchasing.
We adjusted the offer prices yesterday for the upcoming Summer calendar offers to fix the disparity between the Android and iOS prices. Unfortunately, due to a caching issue with the App Store, the adjusted offer prices aren't shown correctly until the game has restarted. You can solve the issue by force closing the game app and opening it again.
We sincerely apologise for this error. If you have bought the offer and were shown the incorrect offer price, please submit a new support request and we'll get in touch with you.