Chinese Renminbi (RMB) is used by Tibetan as currency, or Yuan. 8.3 is the current rate of the Yuan to the US dollar.

Renminbi (RMB). The basic unit is the yuan.The exchange rate is about USD 1 = 8.278 CNY (approx.) Banks in Tibet/china are closed on Saturday & Sunday. If it is cash dollars, even local people help you to get them exchanged in Chinese yuan. Travellers cheques & credit cards are very difficult to be cashed outside the banks especially outside Lhasa.
Tibetan currency
         
Money Exchange

Recieving RMB from automatic teller machines is now possible in Lhasa. There are ATMs in the central Bank of China branch and in a bank not far from the tourist centres. If you are bringing foreign currency to exchange outside of banks (ie when traveling outside Lhasa), it should be US dollars and you should plan to have small denominations (twenties or lower) to change in local hotels. There is no blackmarket for currency exchange in Tibet.

Credit Cards

Credit cards are accepted at the expensive hotels in the large cities such as Lhasa and Shigatse. Other than these cities, acceptance of credit card is very rare. This will undoubtedly change in the future but, right now, it means that you need to use cash for most transactions.

Budgeting

Costs in Tibet for daily living are much cheaper than in the West, although higher than in some other Asian countries such as India or Vietnam.The cost is relative depending on from where you arrive. The one budget-breaker in Tibet, however, is transportation. If you stick to low budget hotels, bus transportation, and small eateries, you can get by on US$10-15 per day. However, if you rent a private car and driver and stay in nice hotels, you can expect to spend US$150 per day or more.
         
Shopping

One of the best places for shopping is around the Barkhor, in Old Lhasa. You'll find prayer flags, fur hats, horse bells, saddles, bridles, copper teapots, jewelry, rugs, and fabric.