1) Business model 
Freemium is a pricing strategy by which a product or service (typically a digital offering such as software, media, games or web services) is provided free of charge, but money (premium) is charged for proprietary features, functionality, or virtual goods. The word `freemium` is a portmanteau neologism combining the two aspects of the business m.....
A game that is free to play but offers additional DLC through microtransactions.