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.
Often, what happens is that we run into unscrupulous Internet Marketers (IMs) who have less-than altruistic intentions of extracting money from you rather than helping you to make it. However, this isn't something new. People have been falling for networking marketing, pyramid schemes, and affiliate marketing scams since before the start of the net.