I'm a prospective math major going to college next fall. Are there any cheap or free math programs available for a graduating high school senior during the summer? Research sounds exciting but I'd be fine with just learning material. By the end of the year I'll have learned basic abstract algebra (dummit and foote), linear algebra (axler and halmos), basic real analysis (baby rudin), multivariable analysis (baby spivak), and basic complex analysis. I don't have much in the way of formal credentials since I picked up most of that stuff from reading. I'm guessing that REUs are out of reach. Thanks in advance for any suggestions!