DNA Heritage is the same company that brought us the best (and only) tutorial available. Here is a page with their rates. They answer many Frequently Asked Questions in this section and this test would tell us enough about who we are to know if we are Russells or not.
Family Tree DNA is another group also available for tests. The FAQ is here and the prices are here. You can view information about the Surname Projects they host here.
Ancestry also has their own DNA test and it's cheaper than the others but price isn't the most important thing, accesibility is. If you have results for another company you can enter them here on ancestry. Their FAQs are available here. They even have the Ancestry DNA Blog! This is a blog entry about the number of markers available and what the differences are.