I've had a look over the site's and there parent companies, the parent companies are allowing them to resell domain name registration for a percentage of each sale. WildWestDomains for 1 is charging each .com reseller around $7 a domain, yet they are selling the domain for $2? I don't see why they would paying $5 for you to have a domain name. It doesn't seem reputable to me, I'd go with a Web Host or some other form of registering a domain name, most web host's depending on the package will give a free domain with paid hosting. Depends on what you are needing the domain name(s) for that is.
For domain names if I am right Yahoo resells for Melbourne IT, wonder if there is any change in this arrangement?