We typically use credit card signup reward miles to travel long distances such as the USA to Asia or Asia to Central Asia or Europe because we enjoy business class fully lie down bed like seats (and the service, the wine, the meals, etc….yes we’re spoiled).
When flying within a region (within the USA, within Central Asia, or even Europe back to the USA) we explore low cost (cheap) flight options. In the past I have used flights.google.com to search but I’m starting to expand my tools.
Here’s a good article that explores a lot of options: https://mikeandlauratravel.com/best-website-for-cheap-flights/
I’ve just signed up for a 30 day trial of www.faredrop.com which was developed by Kara and Nate (https://karaandnate.com/). I suspect that Nate is providing a front end to data from one of the notification options that Mike and Laura listed on their website…but they listed faredrop as their favorite. I was intrigued by http://www.mightytravels.com and might sign up for a 30 day trial to compare it against faredrop (also has a 30 day trial).
I’ll edit this page as I explore these options more. Usually within Asia I also search www.airasia.com because I have gotten lie down seats between Beijing to Kuala Lumpur for $250 each and inexpensive flights of 1-2 hour in economy.