It can be complicated. For these schools, know that most won’t give any need based aid (beyond any federal aid) to OOS students (of course run the NPCs to double check.) Then look at websites for what merit scholarships are open to OOS students, their highest amounts, and whether the student must demonstrate need to qualify. The CDS can be helpful to see what proportion of students receive merit aid and how much on average.
The reality though is that a student might have to apply without really knowing if the money will be there, making the school unaffordable if they are accepted. It’s fine to take that risk, as long as one has at least one affordable highly likely school on the list.
Lastly, there are publics that start at a relatively low COA before discounting (all financial aid is discounting.) These are schools like Central Michigan, Western Carolina…see this thread for some more: Public Schools with No or Minimal Tuition Differences for Out-of-State Students and this one, but it’s a bit dated: Which state schools do not charge an OOS rate? And will also give merit?