Augment runes have been in the game for a lot of expansions in a row by now. These consumables can usually consistently be flipped as demand closely follows the weekly reset schedule.
Raiding consumes spikes during resets
This is just the way it is. A new reset means new raids, new bosses to kill and more consumables needed. This leads to generally very predictable weekly patterns. You can take a look at the prices on a random realm, shown below to see the characteristic spikes. You can take advantage of this trend, as it is very stable, outside of patch launches it will remain relevant.
Check your realm
To do this effectively you absolutely have to check your own realm. Take a look at theunderminejournal.com for your realm. Then you can identify what the low and high price points are likely to be. I would look back about 4 to 6 weeks to get a good idea of what the current market generally conforms to.
The price will trend down until 9.1
I get a ton of augment runes from my mission table. These are quite abundant if you actively focus on getting them from the table, so the price will likely continue to trend downwards until 9.1. This means you should take care to not buy too many at the time. You will want to test with smaller quantities and then scale up until you hit a level where you don’t sell out every week. At that point you are at saturation.
Use the base AH UI
I would suggest doing this primarily with the base AH UI and pen and paper. Write down your buy and sell limits based on your analysis on TUJ and then act accordingly. TSM sources will seldom reflect the edge you are trying to exploit in this market, so it will not be too useful. It’s also just a single item, so both buying and reposting with the base UI is quite fast.