Right now Porkbun has the cheapest first year at $14.24, and Sav the cheapest renewal at $26.46. Over three years the lowest total at one registrar is $70.20 at Porkbun.
Why does .london cost more after the first year?
Many registrars sell the first year below cost and recover it at renewal: at Porkbun, .london renews at $27.98 after a $14.24 first year. Compare the renewal and 3-year columns before you buy.