NB - Click here if you are looking to rent a house in Bali!
One of the first things to note is that, similar to renting a house/apartment in Bali, long-term rent is usually paid in a lump sum in advance for the 6-month/year period of tenancy as, from the owners' perspective, anything less would not be worth it compared to renting it out short-term to tourists. Unfortunately, that is the way it is here - although you can find monthly villa rental, this usually equates to a much higher price for obvious reasons.