This is a fantastic idea and has the potential to bring in a lot of profits. Check out this site (no it's not mine). The premise is similar but they rent all kinds of stuff and allow other people to list their stuff on the site to rent out too. Charge a fee for users and take a piece of the rental profits. It's one way to do it without investing a ton of your own capital. Might not be what you had in mind but they... Source: about 3 years ago

Ruckify.com - known mostly in Ottawa, did not seem to pickup in Toronto. Source: about 3 years ago

You can also check sites like Roomi or Craigslist to see if there are people looking for roommates. Source: about 1 year ago

Go to https://roomiapp.com/ and put in your budget. Anything off the L will give you pretty quick access to nightlife hotspots in Bushwick, Williamsburg, and East Village. If you're on facebook search for Gypsy Housing, lots of folks looking for roommates on there. Source: over 1 year ago

Https://roomiapp.com - Rent rooms and find roommates in a verified community. Source: almost 2 years ago

And lastly, most people look for apartments via StreetEasy but given you are looking for an open room in an apartment with other occupants, you might want to give Roomi a try. Source: about 2 years ago

I’d actually recommend Roomi instead of Airbnb, since Airbnb is going to be very expensive and you’d end up with a room in an Airbnb anyway. Here is a filter for Brooklyn for your budget and here is one for Manhattan! Source: about 2 years ago