Lots of AYCE Indian lunch buffets here on Devon Avenue in Chicago, under $10 last I checked.
The Key Bank corporate HQ’s cafeteria in downtown Cleveland used to not mind if you didn’t work there but were presentable and didn’t hog a table; my book club met there several times. Good food at good prices, and they always had a hot lunch special and a gourmet pizza station. But a couple of years ago I guess too many non-employees were going there, so now it’s limited to employees only. You can’t go up in the elevators to the cafeteria without a Key Bank ID.
I’d sure like to find places like that in my neck of the woods–the South Bay area of Los Angeles County, California. (Other than Chinese, that is.)
Two places I often go to that serve very cheap, very good food are Blaze Pizza and Shophouse Kitchen:
https://www.shophousekitchen.com/
Both serve meals that are under $8.