Six mythos packs? So the starter set, the carcosa expansion and six packs. What packs exactly and how much would all that cost
Would that let more than two people play?
Edit: Is the Path to Carcosa and The King in Yellow the same expansion packs? They're sold as separate boxes.
Okay, it looks like you're looking at the "King in Yellow" expansion for Arkham Horror (the board game), not Arkham Horror: The Card Game. If you're looking at the board game (which is an older game, that is overly complex and a little bit dated), then you'd need the base game (Arkham Horror), and then the King in Yellow expansion, and you'd be good to go.
The card game provides a much richer narrative experience, and follows campaigns that run eight scenarios. It is marketed and released as what they call a "Living Card Game." That means that they release a new pack of cards (usually) every month, and that will contain a single scenario, and some specific player cards. There is no randomization, like there is in a CCG like Magic: The Gathering. Everything outside of the core set will have 2 copies of all player cards (which is the max for a single deck). You'll have enough cards though to put together decks for two players, for sure. The most recent campaign that just wrapped up focused on The King in Yellow, and was very good.
Cost breakdown for both @ retail prices (although I'm sure you can find them for much lower than that at various online retailers.
Board Game: Arkham Horror ($59.95) + The King in Yellow ($24.95) = $84.90
Card Game: Arkham Horror: The Card Game Core Set ($39.95) + The Path to Carcosa Deluxe Expansion ($29.95) + 6 Mythos packs ($14.95 each) = $159.60
There is also Eldritch Horror, which is a board game that is esentially a more streamlined version of Arkham Horror. I see they also have an expansion called "Signs of Carcosa," so I'm pretty sure that focuses on Hastur as well. Pricing on those two products would be the same as the board game and its expansion.