you need to be more specific, are you wanting a .COM, .NET, co.uk, .de, .jp, etc etc Different registars have different prices for different extensions I use these 3 mainly Namecheap.com Name.com Dynadot.com
I would say name dot com coz they offer many free service such as free private whois. And it offer period is friday pricing is low.
I would also try Dynadot if you arent sure of the name, you can delete the name for credit within a few days if you change your mind
Google "Godaddy coupons" or "Name Cheap Coupons" and you will find some pretty cheap domain name coupons.
You can also look at EBay. They have domains for sale and you might be able to find one there that you can use. The price might be cheaper, although you may not have it for a full year b4 having to re-register it. At least you may have enough time to see how it will work and not be stuck with a domain that isn't working for you for a whole year.
you can try Network Solutions... they have a promotion code: 50% off your domain private registration with a new domain purchase online (.com, .net, .org, .biz, .info, .name, and .us) Coupon code: BCXXX03214 (expires 11/30/2009 ) here's a list of web hosting coupons and promotions: http://pocketdeal.com/deals.aspx?categId=82 Or, you ca try http://www.savingpass.com/coupons.aspx?cId=82 I'm looking for good coupons daily on these sites.
I always choose Name.com , I don't go for other Companies because if ever i want to sell my domain it is really not convenient to have it on another Registrar, Name.com is very popular and almost everyone who domain's does have an account at Name.com so that is why they are my Long-term Domain Registrars, They are great!