Resources to find cost after aid?

What state are you actually in? I don't know of any resources that will rank schools by average cost after aid in a way that's accessible—primarily because it's not a very useful metric (because it's an average, the results would vary widely). You're better off checking specific schools and using their net calculators to see your approximate price. But you can try this article, if you haven't seen it yet: https://www.usnews.com/education/best-colleges/paying-for-college/articles/paying-for-college-infographic.

But realistically, if you need a school that will be less than 12.5K/year and you're dead-set on public schools, you need to look either entirely within your own state or at schools that are part of MSEP. There's very little chance you would be able to go to an out-of-state school for anywhere near that cost without some kind of tuition reciprocity, and out-of-state public schools that don't have a reciprocity program will rarely award enough aid to get you close to that point.

For context as well, 12.5k per year including housing more or less means you're looking for a tuition bill of $0.00 and a room-and-board cost that's partially covered by scholarships, because room-and-board is usually something like $14-15k/yr. Might be less in the Midwest because of lower cost of living, but it would still at least be around that amount. By that, any school that does not already have very low tuition and/or would not give you a full-tuition scholarship is more or less out of reach.

Also, while you're just over the eligibility limit for Pell Grants (zeroes out at 50k/yr), you should look into your state's grant, funding, or scholarship programs. Most states have their own grant programs that are worthwhile if you're planning on attending an in-state public school. For example, here's Nebraska's: https://ccpe.nebraska.gov/nebraska-opportunity-grant-nog. If that's not your state (was my best guess), google "[state name] college grant programs"