Indonesia strictly enforces a 6-month passport validity requirement - please double-check your passport expiry date. Most passports will require a 30-day Visit Visa to Bali (e.g., Australia, China, Canada, Hong Kong, South Korea, UK, USA, Malaysia, Singapore, Taiwan etc). There are two options: - Apply for a VOA when you arrive at Bali airport - Apply for an e-VOA online before departure via https://molina.imigrasi.go.id/ The cost is IDR 500,000 per person and you can pay by cash (EUR, GBP, AUD, USD, SGD, IDR) or by credit card (no AMEX) For more information, please see the link below https://bali.com/bali/bali-visa-indonesia-entry-regulations/
The currency of Indonesia is the Rupiah, note that most establishments will not take foreign currencies including USD. Most places in Bali accept credit cards, but it's good to have some cash just in case. There are many currency exchanges in town and at the airport which take a number of currencies.