How much does an undergrad math education differ among top colleges?

Does Princeton offer a wider range of grad classes/better quality grad classes to undergrads?

Does Princeton prepare math majors better for grad school? Does a Princeton undergrad math degree improve your chances of getting into a good grad school?

Is it feasible to get a bachelor or even PhD in math, then work in finance? Obviously you need math skills to work in finance. How much economics do you need to know? Do you need a degree, some economics classes on your resume, or nothing at all?