I didn't estimate the cost but server-wise it's less than 30 EUR/month. What's demanding is transcoding but with the new architecture https://docs.joinpeertube.org/contribute/architecture#remote... there are ways to optimize, e.g. do nightly batch transcoding on a cheaper spot instances.

My business model is showcase and archival of my prototyping work. I'm the only account on my instance so there is no surprise with suddenly someone abusing the instance.