Without knowing more the cheapest is free (at the cost of some time). Find a static site generator + template + host on netlify/github pages (use their subdomain, or fork our a few dollars for your own).

Have a look at https://www.odoo.com/app/website . If you just need a website, it's free. You can also add other paid apps afterwards.

Not sure if this fits the bill :

a) blot.im # I am a happy customer. Starts at 4$ per month. b) https://mataroa.blog/ # Not tried this. But looks promising.

There are many ways it can be free, but the free solutions require at least a basic level of tech knowledge to manage and deploy changes. Are you really looking solely at cost?

What's a good static site generator? Roll your own plus pay by byte for text only might be cheaper if you rate limit IPs