RentJuice, an online service for real estate agents looking to better organize and manage their rentals, appointments and leasing agreements -- not to mention advertising campaigns, and client communication -- has brought in $300,000 in securities and debt financing, according to a filing with the SEC. Based in San Francisco, the company is backed by Tim Draper of Draper Fisher Jurvetson and Colin Evans of Sandwith Ventures. John Zdanowski, the former CFO of Linden Lab, sits on its board of directors.