Namecheap is offering dot COM, dot NET and dot ORG new domain name registration or transfer at only $9.61. These offers are valid until 11:59:59pm EST December 31, 2013. Use the coupon code NCHOLIDAYS at checkout to get your discount.
Namecheap is pretty reliable. Their customer service is great. However, name.com offers $8.25 for a transfer. A new registration costs $10.99 though. These rates are for a dot com. However, you get whois privacy free of cost.
Actually 1&1 offers free registration too, and domains are only 99 cents for dot COM, NET, INFO and other selected new extensions after you get your first domain with them, but this is only for the first year and the renewal is costly than it is at Name.com, Namecheap or GoDaddy, near $15 for the mentioned extensions.
The one thing you have to be aware of all of these deals is what happens in the second year. I use Go Daddy for most of my domain buys, because I know that they're going to be somewhere around $17-$19 every year to renew. I believe the last time I used them cheap, they tried to get you to pay close to $25 for a yearly renewal. Yeah, that's a real Christmas present. Forget them. I'll stick with Go Daddy.