Nintendo adds a new wrinkle to its game-distribution system. Here's what you get with a game-key card and how to tell what you're really buying before you check out.

Microsoft customers can save between $20 and $40 on a one-PC, perpetual license of Office 2013 by purchasing a “product key card,” a retail offer that consists of a 25-character activation key.

Nintendo’s barrage of Switch announcements over the last two weeks have also come with changes to the way Nintendo treats physical and digital copies of games. Digital games can now become “virtual ...