When Francis Davidson was wrapping up his first year of college at McGill University in 2012, the then 19-year-old philosophy and economics major wanted to make some extra cash, so he rented out his apartment for the summer.

By subletting his and his roommates' three-bedroom downtown Montreal apartment to vacationers on rental sites like Home Away and Airbnb, Davidson was able to bring in over $14,000, while paying around $5,000 in total rent for the apartment for the summer, he tells CNBC Make It