I think godaddy best place for you. Registration fee is 6,99 + Icann fee(0,20 cent) if you use "cjcdtaker4" coupon code.
Domain.com have an in house special on right now for US names, they sent an email out yesterday but I deleted it so I dont have the code but someone else might know it.
Thanks for the comments. The cheapest I've been able to find is Name.com for $5.99, I guess they're the cheapest from a reputable company
Actually 1and 1 have sale this time that they are giving out biz domains for $2.99 so who wants them recently they were having sale of us domains for only $2.99 which is finished
That option is available from every registrar .. cuz registrars have got nothing to do with google apps... unless I am mistaken. thx GS