This is my take on it, with somewhat realistic numbers...
Pricing has not been determined yet, but it is likely it'll cost MORE than a normal month subscription.
Gold value will be initially dictated by Blizzard, and supply/demand will determine the value later on (I'm not sure if Blizzard will implement floor/ceiling prices).
When the token is posted, the system calculates how much gold he'll receive when it gets sold. This will be a fixed value - it doesn't matter if the price changes between post and sale. Blizzard has the "gold making machine with unlimited supply, so they don't care).
Here is my little story:
My name is Real Life Rich. I have the monies. I don't want to farm gold, but I need gold.
I'll buy the WoW Token from Blizzard, which means I'll buy gold from the official venue. Because I have the monies! I don't want to have any risk with my account. Official ONLY!
Real Life Rich pays US$18,00 for 30-day game time. Puts it into the new Auction House tab - it'll get in line to be sold.
I'm Poor WoW Player. I barely have monies to pay for energy, but I be needing some game time! I can buy game time with gold!
Farm, farm, farm, farm, farm, farm...
Poor WoW Player checks the AH. 30-day game time is selling for 20000 gold.
He buys it and goes out to play for 1337 purples!
Blizzard "official" monies/1k gold rate is US$ 0,90.
Hi, my name is Mister Gold Seller. Blizz is trying to eff me up and take my business!
They'll never take me down! I'm gonna sell gold for the Average WoW Player. That way, he doesn't need to farm, farm, farm like the Poor one!
So, I'll farm, farm, farm - either because I'm chinese farmer or because I run the bots!
Then, there is the Average WoW Player. He may want gold for two purposes:
1. I want gold to buy pets and mounts and gear and other stuff;
2. I want gold to buy game time.
So, for this to be somewhat good for the Average WoW Player:
Average WoW Player buys gold from Mister Gold Seller: 20000 gold for US$15,00. 1k gold = US$0,75
Average WoW Player knows that his subscription is US$15,00 - and currently, on the AH, 30-day game time is 20000g.
Looks good if he wants to spend the gold in game. Looks bad if he wants to purchase game time...
If 20000 gold is more than US$18,00, why buy from Mister Gold Seller? He can just go and buy a token from Blizzard directly...
If we include RISK in the operation, I'd say that the Average WoW Player wouldn't buy above US$0,60 because of risk.
What if the tokens are valued higher than that?
~25k
Real Life Rich buys token for US$18,00 - sells for 25000 gold. Blizzard "official" 1k gold rate is US$0,72
Average WoW Player would buy gold directly from Mister Gold Seller if the price is close to US$0,60 per 1k (25000 gold for US$15,00).
If 25000 gold is more than US$18,00, why buy from Mister Gold Seller? He can just go and buy directly from Blizzard.
~50k
Real Life Rich buys token for US$18,00 - sells for 50000 gold. Blizzard "official" 1k gold rate is US$0,36
Average WoW Player would buy gold directly from Mister Gold Seller if the price is close to US$0,30 per 1k (50000 gold for US$15,00).
If 50000 gold is more than US$18,00, why buy from Mister Gold Seller? He can just go and buy directly from Blizzard.
So, it seems the less gold tokens sell for, the better for gold sellers.
Sorry for the wall of text.