I would stay away from the domain registrars offering low prices for the first year. They hike up the prices for the second year and beyond to much higher rates. At Economical Domains they offer the same low prices year after year with free privacy and theft protection with every domain name.
I would prefer to use Godaddy.com , namecheap and name.com as they are already in the peak of their business. Meaning they are known for this business - Being High Quality Domain Registrar
i think GoDaddy is best because GoDaddy is offering a wide range of services that can satisfy the needs of everyone. in addition to domain registration and reseller hosting services, they also provide SSL, website builder, hosted exchange and more. beside the wide range of services, they offer special discount and lots of features to customers who choose their reseller hosting solutions.
I like Godaddy.com, but you can also try namecheap.com too they are equally good. I think the free subscription for one year is a good start. This way one can easily start with less then $ 10.
i prefer not the commercial ones internet.bs rlsdomains are very good and much cheaper as popular ones like Goddady $ Sharks
Here is a good new web site for comparing registrars based on a number of things such as price, number of domains, etc.: http://www.registrarowl.com/compare_registrars.php