For any person who is new to World of Warcraft or starting a new character on another server, glyphs are one of the worst part of the leveling experience. Why? Because they're expensive. With the redesign of inscription that came with Cataclysm, glyphs take more money make and cost way more to buy. This leaves low-level alts and new players boggled as to how they're going to afford that Glyph of Totemic Recall that just went up for 200 gold.
To that end, I'm avoiding making a list of glyphs that you should have by specific levels. Me telling you that your first prime glyph at level 25 should be Glyph of Stormstrike isn't helpful if you don't have the gold to buy it at level 25, and it doesn't take into account the fact that more utility-focused major glyphs might be more useful at that level. To that end, I've come with a list of glyphs based on usefulness, separated them into two categories: top priority and low priority. Any glyphs not in this list aren't really worth getting while leveling. That doesn't make them bad glyphs -- glyphs like Glyph of Water Walking can be very useful, just not mandatory for leveling on a budget.