If you're building a simple website, do NOT use SharePoint.
The reason being, SharePoint is a vast, complex platform with many features aimed at collaboration. versioning and distribution of content, as well as managing content workflow, and requires a significant, performant and expensive infrastructure to be able to run the simplest of environments.
Unless you have a very large team of authors whose work requires approval, and publishing across many websites in many languages in your company, I strongly suggest against using SharePoint to publish a website.
To answer your query about pricing and availability - SharePoint Foundation 2010 is available from the Microsoft Website, and the licensing comes with your Windows Server licences.
SharePoint Server 2010 has a separate licensing model and you will need one CAL per user who will access this, or an Internet Connector licence which can be very, very costly.
In addition to the licensing costs, you will need staff and time to maintain the hardware infrastructure on which your SharePoint environment runs, as well as maintenance of the software environment itself, and development/consultancy/training for installing, configuring and building the environment to your specifications.