There's a university, seeking sponsors to lower tuitions costs drastically as they redevelop their online learning platform. And Sponsorship gets your logo published on their site along with a link to your site. You can see the link and get instructions for how to sponsor them at: AdamSmith.edu/sponsors/ Domain is 25 years old! And it's a real .edu site, not one of sub domains like .ac.uk or .edu.ph. So if you can afford a high quality, permanent education link, go for it.
I see the sponsors sign up page, but I don't see where they have put sponsor's links. Do you have a URL for that?