Charmander evolutions

i'd say save ur candies until you get 30 thats when u start getting better cp pokemon.

I would evolve it. If it has one of the 2 best moveset for charizard, WA/FBorFT, I would keep it until I get another with better ivs. Once you lose hope, pow it up, since it takes too long to get candies and it is hard to get a nice moveset, fck it. Since trading will become available some day, if you have 2 or more nice charizard, you could trade it for another op mon. Level 27 is a nice level to start powing up nice mons.

"457 Charmander with 15/13/10 84% IVs"
Its already a good type of Mon to evolve and power up if it has a good move set. Having 15 Attack is a good one. Evolve it... And good luck for a good move set...

Wait until the event ends. While the event is ongoing, you have a decent chance of catching one with higher IVs and/or a higher level.

You might as well wait until after the event and see what your best candidate is then. There's always a slim chance of a better candidate being caught, although this one is pretty good.

Keep collecting the candies - if whichever one you evolve has a good moveset you'll want them to power up, and if you get WA/DC you'll want them to do a second evolve.