Look i think you all are complicating too much, lets put some facts here okey?
First Karma = Exp
Concepts
Karma: Is the sum of actions you make, be it good or bad you will sooner or later pay for it.
Exp: as a general concept comprises knowledge of or skill in or observation of some thing or some event gained through involvement in or exposure to that thing or event.
Ok we got that, now how about the world of Shadowrun, a post modern hell where loyalty is close to non existence and capitalism has evolved into a perverted level were corporations rule your life directly or indirectly, where knowledge and experience is something valuable, and where you can obtain anything on the matrix, simple i follow this rule when a player wish to change karma to money:
First of all i follow this rule: 1 karma = 2500
- Notoriety + Street Cred * Net hits on negotiation. (Yes, i favor the characters that have the skill, if he hasnt negotiation he cant default with charisma. The negotiation test is cheked against a test that the game master makes witha dice pool equal to the Karma being exchanged, the player can use edge on this test.). Also a character can only convert your attribute Logic (Only Cyber and Bioware applays as a bonus you cant use magic for this test because the logic has to be permanent) as karma points to money per sesion, for example:
Carlos Plays Manuel a Street Ganger from "Los Encantos" Seattle city gang with street cred 3 and notoriety 1, and he has logic of 4(5) (Bio-implant that grants him a +1 modifier permanent or passive) in the las fight he ran out of bullets and he wish to buy more but he is broke, so carlos decided that Manuel needed some extra cash fast as he has not used 10 points of karma, and he hasnt transformed that sesion any karma to money he ask the master to exchange some karma for money, so he wish to exchange 5 karma points:
5 Karma = 12.500
Street Cred = 3
Notoriety = 1
Negotiation = 1
Charisma(average for me) = 2
Opposing Dice for the test = Karma Being Exchanged
Net Hits = 2 (Lucky son of a...)
So the maths go like this
12.500 - 1 + 3 * 2 = 25.004
Now these are the maths now how does the nuyen gets to him? easy the characters always have some skill that makes them special and they keep researching on the matrix because hell they wish no know how has evolved so they go to their regular page and they find an add requesting for help (acesoria, i cant remember how was in english) the shadowruner negotiates the price of the "technical help" he shares the knowledge and he gets paid via bank account. Easy and logical not some magic mumbo jumbo that can only be accesed by the awakened.
Now the other part Money to Karma, i handle this a bit... capitalism, first of my rules is that you dont get the karma to spend it on whatever you like no, you pay for a teacher my formula is like this:
Teacher Rating(The raiting must be equal or superior to the rating on the skill you wish to achieve) * Cost of the advancement in Karma * 10000
Now why so overpriced? because you will have to make a Logic + Teacher Hits or Rating to simplify 1 Day(Depending on the skill i encourage the game masters to modify the time as they see fit but 1 day is minimum) the treshold of this extended test is the cost in karma of the advancement you wish once you have it its yours. And thats how you trade Money for Karma.
Sorry for the crapy english but i cant do much about it. Hope i helped a bit.