If I were you, I wouldn't spend more on classes that you can easily farm for (or bot, considering this is a hacking/botting forum)
This is what I would do if I were you:
-Save them for rares (Nulgath rare shop is coming later today, and a Dage one should be coming later)
-Save them for the new naval commander/naval commander class
-Use them for things that unlock items, and you can sell the item back within 24 hours (includes Undead Warrior for legion, treasure map, Warp Necromancer, Infernal Caladbolg, and maybe(?) a few others.