There is an Online Mode, Multiplayer Mode and Story Mode.
You have your own room in Online Mode. You can buy stuff for your room (such as expansions, items, furniture, and others). You can also buy a special feature where you can draw and make your own stuff (excluding expansions). You can also sell your items for Coins. You buy everything with coins.
If you go outside your room, you can interact with other users and their doodle characters.
There is a shop feature in the game, as mentioned above.