Right now Name.com has the cheapest first year at $5.99, and Porkbun the cheapest renewal at $22.66. Over three years the lowest total at one registrar is $51.31 at Porkbun.
Why does .giving cost more after the first year?
Many registrars sell the first year below cost and recover it at renewal: at Name.com, .giving renews at $40.99 after a $5.99 first year. Compare the renewal and 3-year columns before you buy.