Best way to run an instance for cheap is on your own hardware, but I would only do that if you are experienced with self hosting since it would require port forwarding (unsecure if done wrong)

There is !fedia@fedia.io but that place seems inactive. I couldn’t find a status page listed in their sidebar. When I was looking around it was very slow so it isn’t just a problem with you

Seriously, with views like his I don’t know how he ended up owning a place like tumblr