You could make money from renting out a room in your house, or even your entire house over the holidays or vacations to maximize profits. You can list your space on websites like Airbnb, SpareRoom and Craigslist. However, in the US, rent control functions as a price ceiling, putting a limit on rental prices and lease renewals. It is in effect in four states: California, New York, New Jersey and Maryland, as well as DC. If you do decide to take in a lodger, be sure to let your mortgage lender and buildings and contents insurer know in case you are breaching the terms of your agreement. Investopedia also recommends checking your local and state tax rates to be sure you'll turn a profit.