Just booked some flights to Bali for next week for a snip at £349, so thought I'd share it.
Flights are with Garuda and you may be surprised to find that they are consistently now voted one of the best economy class airlines. Good seat pitch and service.
Flight times are excellent (some of the shortest to get to Bali) with short layovers and one stop in Jakarta/Singapore. I only checked for November, and have provided a link to an example set of dates.
Use skyscanner to explore other dates