I remember $4/per semester hour. I think I only spent one summer there and co-op’d the rest, but it was pretty laid back.
At Texas Tech in the early ‘80’s - $4/semester hour also. Summer school was great - no crowds, easy parking, serious students, etc. Started Tech in the summer of 1980 and remember the heat wave as well, especially when I had to move to the unairconditioned dorm for the start of the fall semester. Hot!