How much is a ticket from Tokyo to Oita?

The cheapest price found today is $40.

When is it cheaper to fly?

Cheapest month is September — from $40.

Cheapest today — $40. Below is what booking services offer.

Departure	Airline	Stops	Price
Sep 8	Jetstar Japan	direct	$40	View
Oct 5	Jetstar Japan	direct	$43	View

How much is a ticket from Tokyo to Oita?: The cheapest price found today is $40.
When is it cheaper to fly?: Cheapest month is September — from $40.

Links to booking services are affiliate links. The price stays the same for you.