At game start you are assigned a house that you first spawn in. You own this house. You are able to purchase other houses and use them as Fast Travel points, as well as sell houses or rent them out for passive income.
To buy/sell houses you must be inside and close to the center of a house that is allowed to be purchased. Not all houses are allowed to be purchased. When in a valid house and near the center the "Real Estate" menu option will be active.
You cannot own zero houses. The game will not allow you to sell your last remaining house. A house that is currently set as your home also cannot be sold until you set another building as home.
Neither the sale price nor the rent of a building is a flat figure. Each building type has a base price and a base rent, and both are then scaled by the population and the stability of the nearest town. The same kind of house is therefore worth more in a large, settled town than in a small unsettled one, and a building's value moves as that town's situation changes.
When you rent out a property, you'll receive passive income from tenants. Rent is settled once per in-game day, at midnight: whoever rents a building pays, and whoever owns it is paid. A renter who cannot afford the payment stops renting. Here are some important details about the rental system:
There are soft limits on how many properties you can own. If you reach the limit, you'll be prevented from placing more properties, but there are no other restrictions or penalties.