Sure, but if the machine is already running, it's free. Or if you can stick it in a cupboard at work/university, it's free.
> 0/month
is there actually free cloud hosting? don't they ask for your credit card first before they offer you "credits"?
It still has costs for admin and electricity (via extra CPU load), though I grant these could be marginal.
>Or if you can stick it in a cupboard at work/university, it's free.
This is using someone else's resources, rather dubiously ethical. I suspect IT is going to have a fit when they find out - assuming they didn't block the relevant ports in the first place.
>is there actually free cloud hosting? don't they ask for your credit card first before they offer you "credits"?
There are free plans on Azure/AWS/GCP. Asking for credit card data does not mean you are being charged, I suspect it's really more about identifying users.
It's possible to set up free plans without credit card if one has some other id (e.g. Azure's free plans via MSDN). A prepaid card should work as well.
I was comparing the payment to buying or operating a server (even a free old server has costs, e.g. for electricity). In truth, a proper modern comparison should be to a free plan from one of the cloud providers which is likely to be 0/month.