Some private colleges are old and have had a long history of successful alumni who give back + longtime good investments + patents/research. All of that generates revenue that is given back through financial aid. Other private colleges have very little endowment and barely manage to keep going, thanks to students’ tuition, so they rely on students paying full costs or nearly full costs except for a handful who receive a scholarship.
Among public universities, some receive good funding from the State, some States have excellent financial aid for their residents, others offer scholarships for stats, some other states offer little financial aid and/or fund their universities poorly. Look at what’s happening in Anchorage right now or the Bright Futures program in Florida or Cal Grants in California. Finally, most states have realized that to be attractive to investors and businesses, they need a highly educated workforce. In the 21st century, many jobs will depend on a college degree (certificate, associate, bachelor), yet their population is not commonly well-educated so they try to attract excellent students from elsewhere since once students leave a state they tend to stay in their new region (which is why BF or Excelsior exist, as otherwise talent would just go elsewhere): through its scholarship program, Alabama has successfully managed to attract excellent students from many states, including Illinois, New Jersey, and California.
There’s such a thing as ED1 and ED2; I don’t think you can apply ED1 if you apply through QB but you could apply ED2. Look up which universities have ED2 among the colleges on your QB list.