Roofstock, a website that lets investors find and purchase tenant-occupied single-family rental homes online, is offering a 1 percent referral fee to real estate agents for referring an investor who buys any of the properties listed on its site.The company, which has raised $13.25 million in funding, currently only carries about 70 listing scattered across Florida, but it has plans to soon expand to Las Vegas and Atlanta, as well as a number of other markets in the coming months.The startup posts exclusive listings owned by institutional investors that have snapped up single-family rentals homes en masse and are now seeking to offload them. Earning referral fees Roofstock is designed to make it easy for investors to buy and manage homes without living near them, so agents ...