After about two weeks, the extreme volatility of the first few days has subsided. Prices fluctuated between 87,000 and 91,000 gold over the Feb 18-20 weekend, but intraday price variance continues to be high relative to historical standards, and it's still unclear whether these prices are sustainable in the long term, or whether they reflect the temporary impact of a handful of players dumping lots of gold.
Fully rested experience (this is the blue color your experience bar takes instead of purple) grants 200% more experience per kill. Quest experience does not work the same as mob experience. Instead of just using the rested bonus, quest experience pushes the bar further upwards extending the rested bonus. Say if half your experience bar is blue. If you turn in 10 quests all at one the normal experience from them all could boost a character a full level. Unlike mobs where the experience gain will use up said bonus - the quests merely 'push' the bar further. Doing this could net you a level and still have the 200% bonus for mob kills applying to milk the rest bonus.
Though related, this is no longer true. You can now purchase a lvl 90 character boost. Some power levelers have hoped for a day when you could use real money to buy individual items in-game, some times called "micro-transactions." At a Game Developers Conference 2008, Rob Pardo gave a strong indication, Blizzard would not ever go this route with World of Warcraft.
In 2015, Blizzard started letting players buy gold from each other using WoW Tokens, to try to control the process and mitigate damage. “Time is money, friend — but sometimes one is harder to come by than the other,” Blizzard says on the official page. “Now World of Warcraft players can use the WoW Token in exchange for game time or Battle.net Balance!”