Yes, there are multiple flights from Bangkok to Miri for under ฿ 6,004. The cheapest flight booked recently is on Multiple Airlines for just ฿ 4,713, but on average you can expect to pay ฿ 8,855.
Malaysia Airlines is one of the carriers that may have flexible change policies. You can use our site to filter for other airlines that may also have this kind of flexibility.
There are no direct flights from Bangkok to Miri, but Cheapflights can provide you with all the information you need to find the fastest route with the fewest stops.
For as low as ฿ 12,008, Malaysia Airlines can have you in Miri from Bangkok in 7h 25m. When browsing for deals, the options you’ll see will be for both direct flights and flights with stops.
AirAsia, at ฿ 5,764, was found to be the cheapest airline from Bangkok to Miri. An alternate airline flying to your destination would be Malaysia Airlines.