Digital Den is an electronics company featured in Grand Theft Auto V.
It is a provider of electronic equipment and accessories. Digital Den stores sell Facade, Fruit, Genic, Tinkle, Badger and Whiz products. The company has seven stores in the city of Los Santos, although two are closed and none of them are accessible to the player.
Based on the font, colors and business they're in, it is very likely a parody of either MetroPCS or PC World. It could also be a parody of RadioShack , (Digital/Radio, Shack/Den), and both sell general electronics in small format stores.