QUOTE (Muspellsheimr's Karma Character Generation Rules)
Optional Rule: Gamemasters may allow Karma <-> Nuyen exchange during game play. The conversion rate is 1 Karma per 2,500 Nuyen, or 2,500 Nuyen per 1 Karma. This can be explained as good luck with the lottery (Karma to Nuyen), donating funds & time to a cause (Nuyen to Karma), or anything else that feels appropriate for the character. Characters may only exchange 1 Karma or 2,500 Nuyen per game session this way. Gamemasters may allow an increased number of such exchanges in sessions with extended downtime, at their discretion.
I use it at once per in-game week.
QUOTE (Maelstrome @ Jun 22 2009, 12:01 PM)

normally i run it at 10k to 1 karma but last game was a little nuts with 5k to 1 karma. it really depends how generous you are with both. if you give 5-15k a run i would say 5k is fine. if you give much more than that adjust accordingly.
A run should pay ~2,500:nuyen: for each Karma earned, to maintain balance between Mundane & Awakened/Emergent. Thus, a run should pay ~20,000 per character, post-expenses, as of SR4A (suggested 8-9 Karma award).
In line with this, Nuyen <-> Karma trade should be 2,500 <-> 1