The RU server had a brief premium shop error yesterday, allowing us to get a glimpse at the price of the tank. The bundle is around 60 €. A 10% discount applies for each completed marathon stage. For example, completing 6 out of 10 stages will cut 60% of the starting price. Purchasing it will give you all the rewards for the unfinished missions and will automatically complete them. You will not have access to them anymore after purchasing the tank. It goes the other way too, if you complete the marathon you can no longer buy the bundle. The bundle can be purchased once per account and cannot be gifted.