Have your oldest look into Phi Theta Kappa. It is a cc honor society. My nephew is in it and the college he is transferring to has an automatic $3500/year scholarship for PTK. That plus other automatic merit means he is paying almost no tuition. I will admit I haven’t found another college that offers that much for PTK but I haven’t looked many places.
I’ve been looking around at small public schools in the Midwest and there are some with good auto merit for good test scores. I go to Wikipedia and search for example “Colleges in Nebraska” and for most states there is a list which charts them out by size, etc. I then go to each school’s website and check out the cost and auto merit my daughter will likely get (can’t wait for the February ACT, then we will know more what is in range). I’ve found 3 so far with full tuition scholarships at achievable ACTs of 27-30. And many OOS that will give in-state rates for students with decent stats. California and surrounding states may or may not have any deals like that but I would say just start hunting.
My oldest did win a national scholarship that I think we found on Sallie Mae, for $1500 renewable. At community college that covers a large portion! It was related to her major of graphic design. So it is possible to get something out of those sites, but not very likely. And it depends on your situation, whether you have need based aid that would be taken away. She did not have any of that. She also got local scholarships.