http://www.newsweek.com/pokemon-go-gen-4-update-evolutions-candy-1172975

Gen 4 is finally live in Pokémon Go, and a big part of collecting the new ‘mon is evolving Pokémon.

Luckily for Pokémon Go players, the Sinnoh Region Pokémon released on day one  won’t need too much candy to evolve. There are some exceptions, like the Gen 4 starters who need 125 candy to go from stage one to stage three. However, most only need 50 candy to get to their final stage.