More workers can now use pay advance apps for quick cash to cover expenses between paychecks. The apps may offer no-cost options, but most users end up paying fees that can total hundreds of dollars a year, a new analysis finds. “They are not free in the vast majority of cases,” said Candice Wang, a senior researcher at the Center for Responsible Lending, a nonprofit consumer advocacy group, and a co-author of a report published on Friday on the real cost of pay advance apps.