The currency in Bali is the Indonesian rupiah. The rupiah is divided into 100 sen, and there are coins of 50, 25, 10, 5 and 1 sen, and notes of 100, 50, 20, 10, 5 and 1,000 rupiah.
Credit and debit cards are widely accepted in Bali, and there are also plenty of ATMs. However, it’s always a good idea to have some cash on hand just in case.