One of my goals with #ONI the single user #ActivityPub profile is for it to be dead simple to install and run.
Today I played with the serverless provider Koyeb, as I have an interview with them tomorrow, and managed to set up a running example in under 10m:
https://youngest-rebekah-go-ap-6df5e35a.koyeb.app/outbox
(Estimated costs are about 3EUR/month)