Each time you build a new residence or upgrade it, you receive a Simoleons. This will be a main part of your earning strategy early in the game, when you can build a lot of structures cheaply. Build City Hall when you reach level 5. You can now collect tax from your Sims. The amount of money that can be collected depends on the happiness of your population. Keep your Sims happy by building parks and other recreational locations, as well making sure that services cover all the residential areas. This will eventually become your main source of money. When your population reaches 8,000, you begin selling your items to other players. Set a price and wait for a deal to be made. The rarer the materials, the more money you can get for them. For example, materials needed for Storage upgrades can be sold at a premium price.