If you search google for godaddy coupons you will find some good discounts. There is always a promotion for GoDaddy. It is true though that domains usually don't go below $7 unless it is a .info domain. GoDaddy has promotions where you get domains for $1.99 with webhosting purchase.
If you mean .info then its possible but if you looking for .com then the cheapest i get is $6 as you can see from this thread http://forums.digitalpoint.com/showthread.php?t=1653853
.info domains are popular for building ministes. Not very good for parking. .com is the best as thats what most people remember when they type in an address. They also rate higher in search engines 90% of the time. I do have a couple of .info doing fairly well.
If your intend is to just buy the name and park it for future sale, then you would not get good names with .com, to be able to do so efficiently. If you are looking to build a site with not so rich keyword, you can get a used one from a frustrated re-seller! Regards, RightMan
You can usually find .info's for a dollar or less on Godaddy and there are a number of places where you can buy .net or .org domains around the $5 mark but more like $6. You can buy .com's for about $7 at a number of popular registers but you will most likely need a coupon code.