If you are looking to buy domain names for cheap, buy from Godaddy. They offer lots of coupon codes.
I think I saw an advertisement that they have .com's for $2.95 now.
I had found some $0.99 .COM GoDaddy coupons. You've to change your currency to USD to make them work though.
I buy domains from GoDaddy and then transfer them to namecheap or bigrock before the expiry date; GoDaddy renewal charges are very high.
I have a couple that are up for renewal and thought about doing this as well since Godaddy does charge a alot.