If you've not upgraded to Mists of Pandaria yet, don't!  Instead, first get the trial.  That gives ten days of time, which are saved when you upgrade. Ten free days!  Yay!

I didn't know this when I started the trial.  At first I didn't realize it had the level cap, which should have been obvious, since otherwise it could make a character unplayable if the trial expired.  Then I thought the time was lost, so I was going to do side stuff for the ten days: getting other characters right up to 86, professions, Molten Core (afk next do a dead Ragnaros and a Jeees as I write this).  But then I wondered, does the time vanish?  Apparently not.

Off to the lost continent!  No, not Pandaria, silly.  I need more eternal air for my MOLL-E!  Northrend, ho!