UCI for business is an excellent option, especially at “almost full ride!” Even if you have the resources for two full-pay years at USC, it makes more sense to grab that almost-free undergrad business degree from UCI and pay USC for a masters program instead. In addition to their MBA programs, they have a whole range of targeted masters programs, including one in Finance that can be completed in 16 months - three semesters plus a summer internship.
Good luck and congrats!