Note: This page is based on an assumption referencing Animal Crossing: New Leaf since the Animal Crossing mobile game is not released yet. Will be updated once the game gets available!
Aside from furniture, you can purchase other items such as stationery, wrapping paper, fortune cookie and medicine. You can expand the store by spending a certain amount of bells worth of items.
The basic store available once you started the game.
T&T Mart
Once you have spent 12,000 Bells in the store, 10,000 for the mortgage and play the game for 10 days, Nookling Junction will advance to the second expansion.
Gardening store addition
After spending 25,000 Bells in the store, Gardening store will be added.
T.I.Y
50,000 bells is the minimum amount to spend to unlock this. You’ll first notice that main store and the gardening store is now unified.
T&T Emporium
You must spend a minimum of 100,000 Bells worth of items. You’ll find Gracie in the top level but, you must complete her fashion check first.