I've determined that the value of a credit is 111,111gold.
I have come to this conclusion from using the voodoo market to determine what was the average price for a generosity voodoo card, which gives a player 500k gold. Generosity cards sell for 4.48credits per card, or 4.48 credits for 500,000gold. I rounded 4.48 to 4.5 and did the math for how much gold are you getting per credit from buying this card. The math determined that per credit, a person gets 111,111gold from this.
By this math, 1million gold is equivilant to 9credits.
The value of a credit is determined by how much a credit can get you on the market, however inflated or how well the market does, determines the value of the credit.