You don't need a big marketing budget to quickly attract new customers. That's according to Dan Laufer, CEO of the rental review website RentLingo, and he would know. He has seen his company grow from 100,000 unique visitors in 2013 to 150,000 a month by the end of 2014, using promotional methods that were low-cost or free. The site generated 85,000 apartment inquiries last year, up from 5,000 in 2013. How can your company create that kind of rapid growth without a big marketing investment? Here are Laufer's tips: