Kevin,
Not sure who has the best pricing, I buy it locally at the local auto body supply house. Price seems to be about average (24.00) as other places....For glassing wings I use 206, gives a bit more working time and as always with epoxies, the longer the cure the stronger the finish. For doing fillets , bonding, etc... I use the 205.
If you need to thin it, which I do slightly when glassing wings, use either denatured alcohol or my preference, acetone.

Todd