Best Buy cuts up to 80% off a selection of games for Windows, Mac, and Linux, with deals starting from 99 cents. Choose in-store pickup to dodge the shipping fees, which start at $2.99 where available. (Orders of $35 or more bag free shipping.) Note that most games require a Steam, Origin, or Uplay account. A couple of best bets:

• The Darkness II for PC / Mac for $1.99 (low by $2)
• Deus Ex: Human Revolution for PC / Mac for $2.99 (pictured, low by $7)