You can grab a WordPress website from the managed-host WordPress.com for free, but it will contain WordPress.com ads, and you won’t be able to have your own custom domain name.

To get rid of the ads and have your own custom domain name, you need to pay for a Personal plan which costs $5/month:

WordPress.com Plan Free Personal Premium Business eCommerce
Cost $0 $5 $10 $33 $59
Custom Domain? No Yes Yes Yes Yes

You can download a copy of WordPress.org‘s version of WordPress for free, but you need to install it on a web host somewhere, either an online web host, which costs from around $10/month, or you can install WordPress on your local computer for free, where you will need to install a free local web server, like WAMP (for Windows) or AMPPS (for Mac).

How many WordPress websites can I have?