I would give it at about lv 20 or so, because Pokemon sometimes need to learn speedy moves before they learn powerful moves.
Either trade someone for a Ninetales, or once you defeat the elite four migrate a Vulpix from one of Pokemon GBA (Firered, Leafgreen, Ruby, Sapphire, or Emerald), and use a firestone of Vulpix to evolve it into Ninetales.
I don't think you have an option of getting a Ninetales/Vulpix in HeartGold. I think you need SoulSilver has a Vulpix. Vulpixes are found near the Safari Area. Then at the Pokemon Dome (or whatever) On certain days if you have enough points, you can get a Fire Stone to evovle Vulpix. Or you can just skip all that and trade it with someone that has one. I have HeartGold and I have a Growlithe from the area Vulpixes are available.
Vulpix into Ninetales.Growlithe into Arcanine.Eevee into Flareon.Pansear into Simisear.Vulpix into Ninetales.Growlithe into Arcanine.Eevee into Flareon.Pansear into Simisear.
to evolve pansear you need to give it a fire stone
the answer to this question is that you don't evolve it after you finish the game go in the hole where the wishcash pond is and give the mysterious voice a fire stone and you can evolve vulpix
Give vulpix a fire stone.
you give vulpix a fire stone
you need to give vulpix a fire stone
Well you do need a fire stone, when you get a fire stone give it to your vulpix. after that go to that place where you evolve your Pokemon and your vulpix should evolve.
You give it a fire stone
you must give it a fire stone to get a ninetales
You need to give it a Fire Stone.
You give your Vulpix a fire stone and it will evolve into Ninetails
u have to give a vulpix to bills grandpa in cerulean city.
you need give an fire stone to make evolve an vulpix you can buy in celadon
Show Bill's grandfather a Vulpix, and he will give you a Fire Stone. You could also get it as a first-place prize in the Bug Catching Contest.
vulpix evolves into ninetails after you give it a fire stone. trust me, i have all Pokemon games for gbc, gba, and ds.