Yes, you can use one SealMetrics account; from it, you can create as many sub-accounts as websites you need.
This means you can log in with your username and choose which website data you want to see. Each website should have its own pixel.
The cost is based on page views, not by domain. So, SEAL Metrics will consider all your websites, add page views, and apply the cost to this total traffic volume. The price will adjust automatically if your traffic increases or decreases in a month. This way, you only pay for your real traffic at any time.
If all your websites have less than 50,000 page views per month, you’ll pay 9€/month. Unlimited domains, and unlimited users with access to the platform.