Free, or $19 / year for Pro
Have a look at https://www.odoo.com/app/website . If you just need a website, it's free. You can also add other paid apps afterwards.
Not sure if this fits the bill :
a) blot.im # I am a happy customer. Starts at 4$ 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
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).