Really, to add to the comment about Lowballing and ripping people off. I think that the only time you can say a person is a lowballer and ripping people off IF the only reason the person is lowballing is so they can resell it for more.
If you are actually going to use the gem, and you manage to get it a little cheaper, more power to you. I wouldn't consider it lowballing unless your buying it with only resale in mind.
I don't get how it could be worth even 30EX, since all it does is give you 20% increased xp gain total on 5
1. non-Support gems
2. if you link them in a 6L
3. and said 6L got the corrupted +1 levels mod
4. which usually makes your build weaker, because you can't do that on weapon switch
while you could also just level 6 gems
1. of any kind
2. in any slots
124%*5=620% vs. 100%*6=600%
So you're probably better off leveling expensive support gems (empower ;)) without enlighten.
The reason I use Enlighten is because I use my Tabula Rasa strictly to Level Up Gems.
Since I use Bringer of Rain, I can't use a chestpiece. However, if you have a chestpiece on before you equip your Bringer of Rain, it can still be used to level up gems. I was always using a Tabula Rasa since it allows me to level up any gem I want in any slot.
Then I got my enlighten to Level 2, and realized I can possible get it to level 5, so I invested in a +1 To All Gems Tabula Rasa.
So I got my Level 4 Enlighten + 1 Level to All Gems Working To Level Up 5 Other Gems 24% faster. :D
litle market doesnt mean little price... Empower has indeed more demand, but more people are levelling one or several ones.
30 ex looks a bargain for me.
This. Supply AND Demand. Level 4 Enlighten has much less supply precisely because it's not actually very useful until it his level 4, unlike Empower which is useful at level 2. Even if you have a +1 to all 6L and a level 3, it's technically still worse than just leveling an extra gem in the long run.