Permission? The caricature copyright is initially owned by the artist (or by the company that employed the artist) and you would need to ask permission. It's possible that the contract with the company granted rights to the university (or the subjects) so before asking for rights, talk to whoever hired the company. Practically you may be able to get away without asking for permission for various reasons -- the artist never learns of your use, the company doesn't want to hassle clients, the artist can't afford to sue. In any case, there is always a risk involved with using the work without permission.
How much would it cost? We can't say but we imagine it would range from $0 (they may want nothing, or just want a small credit) to one or two hundred dollars.
Did we pay for the caricature we're using? No, this caricature of Paratrooper Joe Stim was created 65 years ago and we're going to presume the copyright was never registered or renewed.