Are there any free servers, and if so, what are they?
No, theirs cheap VPS for a few dollars a month, and theirs trial VPS which can last for a week before you need to pay.
And if you actually want your server to run stable, don’t go with the cheapest one.
Linode is one I can recommend.
I haven’t had any down time since they changed my server on a cheap one, I paid $40 for a year, and its been up 24/7 so far since they changed my server, the ones my server was on failed, and they gave me a new one that works better 
Make one for your own :point:
I have my own server ha!