One possibility to consider: You might want to think about getting a bachelor’s degree from your local university, even if this means that you need to be a student there for a year or two, and then apply to other universities for a master’s degree.
I have a master’s degree in a subfield of applied mathematics (specifically operations research). When I was studying for my master’s the other students in the same program (at Stanford) had come from a huge range of other universities. It is very common to get your bachelor’s at one university and a master’s at a different university. Frequently (but not always) the bachelor’s is at a more local or more affordable university, and for very strong students the master’s is frequently (but not always) at a higher ranked university.