Americans under 35 spend 16% more than they earn, on average. College graduates leave school with an average of $20,000 in student loans and almost $3,000 in credit-card debt. This demographic, in sum, is sorely in need of an easy-to-use solution to their ample money woes. "There's this dull throbbing sense of guilt that we should be doing something, but where do we start?" says recent Stanford grad Ramit Sethi, who draws more than 150,000 readers a month to his blog Iwillteachyoutoberich.com. In the past six months, a slew of free online services has popped up to answer this question, offering widgets for budgeting, automatic bill pay, mobile alerts, and social networking. All are fighting ...