Question : What day in the next four weeks has the best fares?
Answer : Since low prices are preferred, look at Feb 28th. As of Feb 20th, it's showing the cheapest ticket sales at $745. That is 33% below the average price for this route, so you can spend that extra money on a fun experience in Bangkok.
Question : Is the price you found a good deal?
Answer : Flight prices change much more than most routes from the United States for JAX to BKK. They vary anywhere from $722 to $4,496. Prices tend to be lower the further out you book.
Question : How long do most people stay in Bangkok?
Answer : Of course you're not most people, but if you were, you'd stay roughly 22 days.
Question : Is price more important than specific travel days for you?
Answer : The lowest-cost day to fly in March is Tuesday. Having flexibility in your travel plans means you can save more, so be sure to plan ahead when possible.