You are allowed to make your own threads to roleplay in but here are some specific areas that you can roleplay in:

Antique Shop
Apartments
Art Shop
Bank
Book Shop
Butcher Shop
Candy Shop
Casino
Clothes Shop
Coffee shop
Pub
Fish Market
Flower Shop
Fruit Stand
Hotel
Library
Music Shop
Photography Shop
Post Office
School
Toy Shop
Train Station
Vegetable Stand

You will be able to purchase many things in the shops in the future but for now there isn't much.