Why do you want cheap domains for? You get what you paid for. You need to buy from reputable companies, or you will get into problems. You should also make sure that buying cheap, the renewal rate isn't high. I believe Name.com renewal rate is $9+ per year after the first year.
I think $6.99 - NO MORE... Even if they advertise this like $6.99... .COM and other generic domain prices went higher on October 1st, most charge about $9 now. If you can pay Epassporte, I can register you .com names for $8 via Directi.