ConstantEnchantmentCost

Normally, in Minecraft, enchanting removes a set amount of levels from the player. This plugin makes it so that instead enchanting removes experience points equal to the required amount of experience required to go to the specified required enchantment level from level 0.

Are you level 10? A 3 level enchant will remove 27 experience points from you.
Are you level 100? A 3 level enchant will remove 27 experience points from you.