If you go to a bigger school, they have multiple graduation ceremonies. Split the rental amongst anyone who does not share a time slot with you.
That’s what I did and people acted like this was a genius move. No, I am just broke.
You can just not participate in the ceremony and then you don’t have to spend any extra money at all.
I just did online school and didn't bother showing up to any kind of ceremony. I was 30 when I finally finished school, I didn't really feel the need to prove anything.
I skipped the graduation ceremonies for my BA and my first master’s degree. For my second, apparently the cost of a cap, gown and hood was included in the tuition so I have academic regalia sitting in a box somewhere should I ever find myself in need of such, a scenario I cannot imagine ever coming to pass.