Black Ops

The $15 price tag for map packs started with 2009's Call of Duty: Modern Warfare 2.

Despite criticisms from players about the hefty cost, the first DLC for the game generated 2.5 million downloads in its first week..

Source: http://content.usatoday.com/communities/gamehunters/post/2011/04/call-of-duty-map-packs-prices-defended-leaks-reported/1