it depends on where you buy from.. normally its anywhere between 7 to 10 $ .. just use godaddy.com with some coupons or cheapname.com
If you will buy from reliable sourced you will get them in the range of 8-10 bucks I prefer to buy from namecheap which costs me 9.xx
less than $10,you'd better try to purchase it from some biggest domain registrars so that you can get some coupon code.
about $6-$10 maybe.. but the price can straight up until $10,000 if that's premium domain it depends at the registrar and the domain you choose
Currently, among major registrars, I think 1and1.com offers the cheapest .com at 6.99$ (First year only) But their procedure and domain management interface is generally a pain in the rear end.
You can get .com domain for first year then it will be normal rates. Generally you can get .com for lowest price for first year at $6.
$8.99 at www.OrderDN.com (+ 1 moth free hosting) Or if you have a CC you can get one from godaddy at $1.17 Good luck
Dear Ann, I am a little confused about your title, "buy...domain", what do you mean by 'buy'? "buy=register? " or " buy=buy premium domain?"