The best domain name price we could find with Netfirms was $7.99 USD for a .com domain name for the first year. (The second year returns to the regular price for Netfirms which is $9.95 per year per domain name.)
There are a few nice things about Netfirms that caught our eye:

Although they’re not the cheapest, [...]

GoDaddy currently has a special rate of $1.99 for any domain (.com, .us, .mobi, .biz, .net, or .me) but you need to read the fine print carefully:

The special rate of $1.99 per domain name per year only lasts for the first year. After that, the price goes back to $10.69 per domain per year [...]

Several of the large domain name registrars allow individuals or small businesses to buy domain names and then re-sell them to other customers. You’re not buying specific domain names and trying to sell those domain names. Instead, you buy a package that guarantees you a lower price from the domain name registrar. Often times, the [...]

Update (Dec 2009): MelbourneIT is still one of the most expensive domain registrars around. They still charge $35 per domain name per year for .com, .org, and .info domain names. There are several cheaper domain registrars offering better deals. Check out our cheap domain price comparison chart to find the cheapest domain registrar.
Best Domain Name Price on MelbourneIT: [...]

Update (Dec 2009): You need to be a domain reseller to buy domains from Tucows / OpenSRS.  Their prices have gone slightly up since the last time we checked. It now costs $10.04 per .com domain name per year. They current have a sale on .info domain names for $3.18 per domain name per year. [...]