Research other listings in your city on AirBnB and see what the going rate is for a place like yours. You could also just rent out a private room as well or even a bed in a shared room. In fact, that's how AirBnB got its start. However, you might find it hard in the beginning without reviews, but as long as you take really good care of your guests and provide a lot of value, the reviews will eventually come rolling in.
If you have a knack for a certain subject and live near a college, consider offering up your brain power and teaching skills for some quick cash. Grade school kids need help too, and parents pay better than college students. You can take this idea to the next level and scale by tutoring online. We have an interview post dedicated to a chemistry tutor who took his skills to Tutor.com. To be successful, you have to have a good grasp of the concepts but also be able to find a way to relate topics using real-world examples.
How much will you make? I think my best month with Google AdSense was almost $5,000 over the last ten years. That amazing month blew my mind since it was actually near the beginning of my blogging journey. When you go from making zero to $5,000 in a month, that will rock your world. For me, it also got me even more excited because I knew there were other ways to monetize.