Go through your results for flights to Hat Yai in Thailand with Netflights. Although Thai Airways International usually has the best prices, it's best to double check what's available for your travel dates.
If these flights are too expensive, try searching for a different time of year. So if your dates are flexible, consider looking at different times of year.
But if you're struggling to find flights to Hat Yai that work for you, try looking at other airports in Thailand.
For even more options, check what other airports you could fly to Hat Yai from. You might be able to make a saving by going from a different airport or city.