Squarespace provides your web hosting (and a domain that's free for the first year if you wish to purchase it from them) and has annual and monthly plans that you can view here.

You’ll need the business plan as it provides you with analytics to view your website traffic as well as integrations like your newsletter host (if that’s not Squarespace) and any customized code needed for your site.

As a Squarespace Circle Gold member, my clients receive 20% off their first year’s subscription.

You can definitely bring a domain you already own that’s registered elsewhere and I’ll connect or transfer it to Squarespace as appropriate. I can help you purchase one if you need it.