I read on boardgamegeek that these would be great character packs to start with...

But I can't seem to find any information on how many of each pack I should buy?

In case it helps, I will probably be the one who will be supplying the cards to all players... and most likely..it will mostly be joust matches with a few melee here and there if it catches on..

Thanks for any help!

It depends on how many decks you're planning to have for each House. If you plan on playing just one deck per house or can trade things back and forth then I'd suggest:
Refugees - just one pack - you'll want the Refugee cards for each House, Cat o' the Canals, Alannys GJ, and Gilly if someone plans on playing Summer. You might want more copies if you want more Cats.
Ancient Enemies isn't as useful as it used to be since the Fury plots are restricted - just one pack - you'll want the Fury plots for each House. Dragon Thieves are also very nice, Bear Island is good, but they both come 3x in the pack.
Sacred Bonds has a lot of great cards and I would say three copies of this one. In addition to providing each House with three copies of the To Be a... event, Stark can snag 3x Feral Pack.
These three CPs all add a good balance of good cards spread across the Houses pretty evenly. The Heralds are also useful cards for each House as are Bringers of Law.

Thanks, Skowza!

And I meant chapter packs