> I know what I'm offering is limited in value relative to what you
  > are offering me, so I am open to give you anything else I could
  > reasonably offer for this mentorship.

Don't undervalue your skillset. If I were a python guru, I would immediately take up the offer and help you out quite a bit for what I would be getting in return. It's just as true that anybody could go online and learn all that "finance stuff" as they could learning all that "python stuff". The value for both subjects is in the mentorship to guide and accelerate the learning. It's not like you're offering home cleaning tips in exchange.