This week's new Fire Emblem: Awakening DLC is "The Lost Bloodlines 1," available alone for $3 or as a $6 bundle that also grants you two more maps when they're released.
Successful completion of this map unlocks a card to summon Leif from past Fire Emblems. If you're a Fire Emblem fan, this may be exciting to you; as someone who has jumped into the series with Awakening, all I can say is that his sword has been pretty good when my other characters have found it.
Other DLC available include three "Champions of Yore" maps and a bundle, and the "Golden Pack," led by the "Golden Gaffe" pack, which promises to earn you lots of in-game cash. It's not like paying for in-game currency because thankfully there's a Fire Emblem map between your expenditure and the virtual money.