We should be able to buy 1 Etheric Light for 100 Vanguard or Crucible Marks. This makes sense given that you can't stockpile Marks, and you would have to max them out for 2 weeks just to get 1 Etheric light. That is a lot more time and effort than simply beating PoE 34. This would give players who aren't interested in PvP, and are unable to find teams to play PoE, a long term way to slowly obtain Etheric Light and upgrade their weapons and armor. Credit goes to MakoSoul.