I bought Netcom4us.com in 2010 from Yahoo small business domain and I think it was the cheapest .com TLD. Yahoo offered $1.99 domain just for first year and for new customer. Its price for second year was $34.95 and I think this price so expensive for me so I transferred it to Godaddy.
In 2011 I bought new domain from Yahoo small business and sadly its price became $3.95 but I think it still the cheapest domain. Today when I open my Yahoo mail, I see advertisement on it that Yahoo small business domain $1.99 is back. So if you want to register your new domain with just $1.99 you can access from Yahoo domain. Base on my experience that second year would be $34.95 I try to change plan to become 2 years or 3 year. Surprise its price just $9.95 annually and I think it is normal price. I hope this is not just a promo so as advice please always looks at the domain plan for second year.
I hope this information will make you comfortable with your internet.