I'm spending less than $5 on Mastodon compatible server
social.minbash.de
2 threads
I did a similar thing with my server, akkoma.sandhill.social.
It's going to cost me about $5 per month (I am using a different cloud server to host it) but together with the $100 credit I got through a promotion I won't have to pay that for some time.
Link goes to the server installed same way. Give it some love :)