The local currency in Bali is the Indonesian rupiah. 1 euro is equivalent to about 17,500 rupiah. For cash, banknotes are mainly used in Bali and more rarely coins of e.g. 1,000 or 500 rupiah.
There are notes of 10,000 (purple), 20,000 (green), 50,000 (blue) and 100,000 (red).
To pay for your purchases in Bali, more and more shops, restaurants, cafes, and hotels accept credit cards. Please note that there is sometimes a fee of about 2% added when you pay by card.
For less modern places like markets, local restaurants, or temples with entrance fees, you will have to use cash.
Note that you may have a lot of money in your wallet in Bali. Indeed, 100 euros is about 1,500,000 Indonesian rupiahs, or at least 15 notes.
What I advise you to do is to keep 500,000 in your wallet, accessible quickly. For the rest of your banknotes, put them in a more hidden and less accessible place.
