The Currency Unit in Goa as in the rest of India is the Indian Rupee in various denominations with the highest being Rs 1000. Beware: Notes of Rs. 500 and Rs. 100 appear quite similar and are easy to confuse.
It is not permitted to take Indian currency out of India nor purchase the Rupee overseas. If you are arriving from a foreign country, you should change some of your currency into Rupees at the airport or at the nearest branch of State Bank of India where you are offered the best rates of exchange.
Money Exchange services are also available at most major hotels & resorts and private money changers in the area. Most reputed banks such as HDFC, ICICI etc also have ATMs that accept Master and Visa Card to withdraw cash.