In the technical sense, yes, every class has an assigned AC cost, which means it is worth* ACs, but paying 2k ACs to save a couple hours of farming is generally not worth it, unless you for some reason want the class ASAP.
Ranger, ToH, Battlemage, Arachnomancer, Evolved Shaman, Lycan, Pyromancer, Cryomancer, Soul Cleaver and so on are not worth it from a power standpoint, so unless it's your only method of obtaining them, the class is Lightcaster, you are gonna buy the class to try it out before farming it, or you have more ACs than you will ever need, then buying a class would not be worth it. Or a mix of any of those things.
*In the sense that it's value is the amount of ACs spend, totally unrelated to the term of a class being "worth it".
< Message edited by Metakirby -- 7/18/2017 18:09:11 >