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 [...]

Update (Dec 2009): After researching over 20 of the top domain name registrars, 1&1 Internet is quickly becoming one of our top picks. The big 5 domain types (.com, .info, .biz, .org, and .net) have a regular price of $8.99 per domain name per year. 1&1 still offers $0.99 for a .info domain name and [...]

Update (Dec 2009): Active-Domain.com is still offering a sale on .info domain names: $2.85 USD per domain name for the first year before returning to the regular price of $9.95 per domain per year. They still charge $5 per domain name per year for domain registration privacy. There are cheaper domain registrars out there who [...]

Update (Dec 2009): HostGator is still charging $15 for a .com domain name (per domain name per year.) There are cheaper domain registrars out there. To help you, we’ve researched the sale prices and regular prices for domain names from over 25 of the most popular domain registrar companies into a sortable chart comparing the [...]