After a recent post on the official World of Warcraft Forums, a Community Manager called Zarhym revealed that Blizzard are :
"...exploring the possibility of adding a way for players in certain regions to make purchases directly within the game..."
The post on the forums was asking for clarification over a new item that had been found by people searching through test server updates. The Enduring Elixir of Wisdom item boosts experience rewards by 100% and is currently only available on the game's public test servers.
Zaarhym also mentioned because of the process, other elements related to this update would likely be appearing on the Public Test Realms.
The response to the post has been fairly mixed, with some players not wanting to offer support but a surprising amount appearing to be ambivalent to the whole matter.
World of Warcraft has seen the playerbase decline in recent months, although there have been attempts to refresh the game to make it look more appealing to new players such as new playable races like Pandas and a free to play level cap (where you can play up to level 20 for nothing) do not appear to have had as much success as hoped.
World Of Warcraft is facing stiff competition from Free to Play games and games like Guild Wars 2 where you buy the game but can play online for free, which already have a simalar mechanic allowing players to buy items, boosts and equipment using real money, so it will be interesting to see what happens with World of Warcraft from here.