My 2 cents:
Travis' point about buying packs cannot be overstated. If you do the math, even from Travis' starting prices you would come out ahead buying packs over buying a complete CoW set (when you factor in the additional cards you get).
Case in point, I bought 3 boxes, so you can figure out what I spent on CoW. I got 1 TSC, 2 Broken Cov, and 1 Eternal Inheritance. I was missing a few rares and commons, but I had so many extra CoW cards that I easily got a complete CoW set through trading.
The reason buying singles is more expensive is Travis, or any vendor, will demand a premium for taking the "risk" of buying packs to get you the exact card you need. Because you don't want to buy a bunch of packs and risk not getting what you need, you have to pay up for that.
So if you need a lot of CoW cards, buy packs and trade. If you only need a few, buy singles. If you need all CoW cards, I recommend buying packs and trading. The big risk with this is not getting TSC of course - but you can always buy packs until you get TSC, and at current CoW card prices, you'll almost certainly come out ahead.
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And all this is ignoring the fact that:
1. CoW was released less than 3 months before Nationals.
2. CoW was probably the most game-changing expansion since Warriors.
With the small window for players to get the cards they needed, and with so many CoW cards viable in top decks, a squeeze of prices up via supply and demand was already "baked in the cake".
