✔ 最佳答案
1. It depends. You can refer to the following for more detail:
http://www.cbp.gov/xp/cgov/travel/id_visa/
2. If it is not considered as a prescription for medical use, it will be your best to check them with your luggage and carry a small amount with you as carry-on.
3. Yes as the airlines company is not obligated to its loss.
4. It depends where you are going. T-Mobile has one of the worst network in the U.S.
5. It depends on how you use the service.
6. Both will cost you a lot. If you can, try IP Phone or similar instead.
7. iPad 3G service is available only with contract commitment without prepaid service.
8. It depends on where you live.