There is. I believe Open Source projects have Golden tier on GL for free and Ultimate on premises. Not sure, you have to check.

edit: just checked:

education: https://about.gitlab.com/solutions/education/

opensource: https://about.gitlab.com/solutions/open-source/program/

But these pages are not easy to find, I had to use search. This should be mentioned on the pricing page.

TBH all these features on Gold and Ultimate for free are game changers (specially Gold since you won't need to manage and install so many things that used to be many different systems), GitLab should advertise it more.