The business model is similar to that of Netflix Inc., which rents DVDs by mail and raised $82.5 million when it went public this spring. Booksfree customers can take out as many as six books at a time, depending on their membership level. The company trades mostly in mainstream books that it orders from distributors Ingram Book Group and Baker & Taylor Inc., but it also boasts a limited number of out-of-print books by romance novelist Nora Roberts, for example, that Ross or Bilinski brought back from book shows. Its most popular book, with several hundred copies circulating, is Carly Phillips's "The Bachelor."