What does enchantment cost mean on minecraft?

Answer 1

Enchantment cost refers to the levels. Let's say you're level 32, and an enchantment you want costs 28 (which just so happens to be Silk Touch), you will have 4 levels left. In order to change the maximum enchantment levels, you must have bookshelves. The bookshelves must be at least one block apart from the enchanting table, and can be stacked up to 3 tall. The maximum is level 30, and you can cut off sources by placing a torch for a specific level. I hope this helped!