Godaddy is the cheapest usually about 7.49 .. but they really kind of suck, such a spammy site.. I personally use namecheap.com , they're about $8.xx and let you pay with a paypal balance.
I use godaddy and find their system very fast and efficient. I always pay using my paypal account they have on file so there is no logging into paypal, its just accepted instantly. very fast, very simple and very cheap
GoDaddy.com! they have tailor made rates you can find their online coupon that can reduce your cost.. Its secure & best in service Dont bother with cheap names! because in domains & hosting price matters to quality
That's why people know it as TrickyDaddy too Jokes aside, the cheapeste dot.com registrar is http://www.domainsarefree.com/ just $3.99, no coupon needed. 1&1 sometimes offer cheaper dot.com without coupen either but takes time to see that offer coming up.
Go Daddy... use code BOWL2010 and you can get 1 .com for .99. You can only get the 1 .com for that price with this code, unless you clear cookies, use different accounts, different CC and all of that.