When the term “financial aid” is used, it is generally being used to describe need-based aid. With the exceptions of UVA and UNC, I don’t think any out-of-state public schools provide need-based aid to students, barring what is federally available (i.e. Pell grants and the $5500 loan mentioned above). If your family is able to provide a substantial amount of money towards your college education, it is unlikely to qualify for a Pell grant.
So, essentially, your budget will be what your parents are willing and able to contribute annually, a portion (say, 20%) of any savings that you have from work or other means, and potentially a federal loan (which is a max of $5500 your first year, and a total of $28k for your entire graduate education).
Scholarships (aka merit aid) can help bring a school’s sticker price down within your budget, and a number of schools have scholarship charts on their webpages or will ask for your academic stats on the Net Price Calculator (NPC) and then indicate a minimum amount of scholarship money that you may receive.
Do not sleep on Missouri S&T. It’s a great school and since you’re in-state, it’s an even better deal for you.