So I'm thinking of a trait (Or set of traits) that give certain skills a boost to Xp gain.
Like each one would give a person a +10% experience boost (or more) in a different skill, but doesn't grant any levels in it.
It would be cheaper than the skill level ones, because it doesn't grant any actual 'knowledge'/
It could be done one of two ways (that I can think of anyways) :
1. It is free, but only one can be chosen (Each is mutually exclusive)
2. It starts low, but each skill bought after the first increases in price.