Right now Dynadot has the cheapest first year at $1.99, and Epik the cheapest renewal at $14.43. Over three years the lowest total at one registrar is $34.97 at Regery.
Why does .cam cost more after the first year?
Many registrars sell the first year below cost and recover it at renewal: at Dynadot, .cam renews at $19.99 after a $1.99 first year. Compare the renewal and 3-year columns before you buy.