You can setup Operational on render.com. This requires you to create:

• A static site(for /app)
• A nodejs webservice(for /backend)
• And a standalone mysql database

Good to know

• The nodejs instance doesn’t need much ram/cpu. You’ll be fine with the $7 p/m plan for a looong time.
• Mysql db can be upgraded if you store a lot of events. Or you can modify the REMOVE_EVENTS_AFTER env var to something shorter(its set up to store events for at least 1 year)