To be clear, there are exceptions. I was over-generalizing. There were natives who had good scholarships, and foreigners who paid, but for the most part foreigners paid very little, while natives paid full or close to full in-state tuition.
After living in Oklahoma most of our lives, but moving to TX before I started at OU, we had to pay out-of-state tuition for me because my parents didn't believe in having me register with family members' addresses in Oklahoma, like my grandmother's.
In-state students at that time, "back in the first millennium," eons ago, paid $7 per semester/hour. Out-of-state (such as *moi*) paid $20/semester hour. Huge difference. I also had scholarships I couldn't use because there was no "need."
I have no idea what the arrangements are nowadays.