You could also host with someone that provides unlimited sub-domain hosting and just do it that way:
mydomain1.mydomain.com
mydomain2.mydomain.com
mydomain3.mydomain.com
.....
It all depends upon what your true goal is? If you want to build back links and anchor text then maybe subdomains are the way to go.
If you are looking to reduce costs below $8.95 for a single domain then I would question the amount of effort it is worth applying.....but .US would save you $4 a year!
Thanks! I was just wondering because my company owns a lot of domains, and I am looking for a way to buy them in bulk for less.
"a lot" as in +/- 100 or "a lot" as in more than 500?
Several of the domain name registrars will give a much better deal to an individual or company that has over 100 domains hosted with them.
There was a company that offered be my domain registrar for $6.50 per year - but I already am getting them for $7 per year from my main registrar, even at saving a couple of hundred dollars per year, I have been with the other company for 5 years and I trust them - I am not ready to risk my business for a couple of hundred dollars with an unknown company.
At any rate, I am too lazy to go through the transfer process hassle. :P
As Leosghost says, why not become a reseller and buy at bulk rates? Go Daddy offers .com at $6.75 bulk plus a $99 a year reseller fee, but don't just look at them - check out a few companies and see what deals are around.