If you are a CA resident then you have available to you relatively affordably what may be the best undergrad preparation for grad school in math in the country. I’m talking about the Math major in the College of Creative Studies at UCSB. For the right student, one that is very smart and ready to take ownership of their future, CCS is a great option. They think of themselves as “grad school for undergrads”. You want to take a course at UCSB, whether undergrad or graduate level, just sign up for it. CCS lets you waive all prerequisites; you think you can do it, they let you try. The school is geared towards undergrads that intend to go on to a PhD program and they have a phenomenal placement rate at the best grad programs in the country.