There are very limited ATM facilities in Bhutan and that too not very reliable, so it’s advisable to carry some cash with you. Only US dollars/Pounds/Euros are commonly accepted. Indian currency is at par with Bhutanese currency and accepted everywhere. Credit card is still not common in Bhutan. Only handful of stores/hotels accept visa card with 5% transaction charges, but lately most of the souvenir shops have started to accept visa cards.