The Federal Trade Commission has sued the popular fintech app Dave, alleging that it entices customers with ads offering cash advances of up to $500 but provides that amount only a tiny percentage of the time while slipping in undisclosed fees.

The 33-page federal lawsuit, filed Tuesday in the Central District of California, also alleges that Los Angeles-based Dave failed to clearly disclose that it charges customers a $1-per-month "membership fee," which it automatically debits from bank accounts, and doesn't tell customers until after they have completed the sign-up process that they must wait two or three business days to receive their money unless they pay an "express fee" of $3 to $25.