Few examples I've come across are:
1. Swiss Foundation + Delaware C-Corp
2. Cayman Islands Holding Corp + Delaware C-Corp
3. Mauritius Foundation + Cayman Islands Holding corp + Delaware C-Corp
4. Gibraltar Holding Corp + Delaware C-Corp
5. BVI Holding Corp + Delaware C-Corp
What structure did you follow? How much did it cost? What were the timelines & challenges you faced each step of the way?
No one is going to answer this question honestly here . There are rivalries all over the place . I haven't done an ICO before but i still have the courtesy to explain a few things here . Firstly , Not all the ICOs pay taxes , Why ? Simple , because their government don't know what ICO is so taking a permission for it is wasting their own resources and time . If your country legalizes the ICOs ( which infact is not easy) the best way to get a tax-efficient structure will be paying some benefit to the government in case you succeed in your ICO. Be sure that you don't set up your ICO in some ICO resistant area ( line USA , China) .