Just tried to use the Auction House for the first time to bid on a pretty cool item. Accidently bid 2,500,000 gold instead of 250,000. No confirmation button and no way to immediately cancel it. So, I'm fucked.
In my opinion, fuck the auction house for anything other than selling off old items. Even then, only if you want little extra gold than you would get for selling it to a merchant.
-420