Right now iPage has the cheapest first year at $5.99, and Dynadot the cheapest renewal at $16.99. Over three years the lowest total at one registrar is $41.97 at iPage.
Why does .blue cost more after the first year?
Many registrars sell the first year below cost and recover it at renewal: at iPage, .blue renews at $17.99 after a $5.99 first year. Compare the renewal and 3-year columns before you buy.