In Tibet the only place to change foreign currency and travelers cheques is the Bank of China. All the star ranking hotels in Lhasa have exchange services but they are only available for guests. The sensible thing to do is to change as much money in Lhasa as you think you need. The only other places to change money are in Shigatse, Zhangmu and Purang. If you are traveling upcountry, try and get your cash in small denominations: RMB100 and RMB50 bills. If you dont like the idea of turning up at the border with no Chinese currency you can buy cash RMB from banks in Hong Kong and the Bank of China in large cities.
Credit Cards: Credit cards are not recommended as a way of payment in Tibet. Flights and Lhasa cannot be paid using a credit card. The Lhasa central branch of the Bank of China is the only place in Tibet which provides credit card advances. A 4% commission is usually deducted and the minimum advance is normally RMB1200.
Travelers Cheques: Travellers cheques are now acceptable at the Bank of China. It is recommended that you cash them in Lhasa.