Why Shadowfist? Well I really liked it in the past. But there are other reasons as well. First off there are few games with very many expansion sets. Really only Shadowfist, Legend of the five rings, and Vampire the eternal struggle (Jyhad) have enough for me to consider. I understand there are loads of new games games produced by Fantasy Flight but I am looking for things i can grab cheaply. Of these Shadowfist and Legend of the five rings are actually still being produced. As for Shadowfist there are actually a couple of planned tournaments at Kublacon which sort of locked up my choice.
I have found the two biggest keys to buying up these cards are patience and knowledge. As for patience I am really getting at waiting on solid deals. There are loads of folks on ebay right now trying to sell off unopened Shadowfist cards. They for the most part are asking retail for their cards which seems crazy. If you wait you can find people offer an old collection of cards every month or two, these are usually around 20 bucks or so dependent on size.
Knowledge really wasn't the best term to use. There are really just a couple of things I realized that I had not thought about. First is a concept we use in Atari cartridge collecting. Some cartridges have no value, you just will get them in the process of collecting. Common and uncommon Cards from the Limited and Standard sets are like this in shadowfist. You are going to get them so don't pay for them. Work at getting cards from any other set Dark Future, Flashpoint, whatever. The second weird thing I found was ebay is not always the best price you can get. That sounds obvious but I mean the seller on ebay may offer an item cheaper on their own website. I have found this to be the case for unopened packs on multiple occasions.
SO where do I look for cards? Ebay.com and shopgoodwill.com have been my primary sources. Moving from The Bay I have no idea where to look for cards here in Portland/Vantucky. If I was back home I would look at places like the comic collectors shop in sunnyvale. Old shops that have been around through the card craziness in the 90's. I scored a box of Vtes cards off those folks for ten bucks. Also check your toad and troll or other online game source. Keep in mind you may want to get more cards than you need and pass them around to folks to give yourself to play against. I have some unopened packs I will think about giving out at to drum up interest.
Update: I sort of forgot to mention the new stuff that is being released. Buy that stuff from FLGS and the kickstarters they release. I would recommend supporting the company as directly as you can. Funding the source of new cards is a great way to support the Shadowfist community.