The glyph market is much more fluid then most. It is still driven by suply and demand. But I dont consider any glyph to have a market price. Market price is the lowest listed price on the AH that day. Think of every glyph as worth 5G. Anything over that is pure profit.
If a glyph is over supplied then its value crashes. All leveling glyphs fall in this trap. Everyone has a stock of them from skilling up and everyone can make them. People think of them as worthless and often times people forget to post them.
Some people think some glyphs should have a higher value. Its that glyph you paid 40G for because that was EJ said you should get and in your mind it is worth 40G. When people get artificial prices in mind they do silly things and get very fustrated when people under cut them and crash that price.
To make lots of gold with glyphs you need to step away from the micro pricing of every glyphs. With automation, let the market be fluid and flux with the price. Post 2-3 of every possible glyph you can make. Some will post as low as your willing to list them for but you will see others post for a lot more.
If you are the only one posting a glyphs, you can set your price. When people need a glyph, they need a glyph. Some people post them upwards to 90G. I like to post those aroung 40G. I do that because if its a crap glyph that they just want to try for something, it is still not that much to spend on a throw away glyph.
I will have to show you a little bit about Quick Auction. It takes the hard work of posting glyphs.