Roblox
Roblox allows players to create games and play games created by others, with many different types of games available. Roblox can be used on multiple device types, being on iPhone, Android, PC, and Xbox, but it can't be played on a browser (Example: Google). Roblox itself is free to play, however, virtual accessories can be purchased in the store using "Robux", a currency which costs real money to obtain but can also be earned by selling virtual items to other players.