Online education provider Udacity is promising graduates of its new Nanodegree Plus program that it will find them jobs within six months -- or their money back. The guarantee will initially apply to U.S.-based learners in four of Udacity's microcredential programs: Machine Learning Engineer, Android Developer, iOS Developer and Senior Web Developer. Udacity introduced nanodegrees, nine-month programs in career-focused subjects such as app development, machine learning and programming, in 2014. The start-up already refunds 50 percent of the $199 enrollment fee upon completion, but will launch Nanodegree Plus as a premium tier priced at $299. The programs are also available for free.