I was talking to Lino yesterday about how hard it actually is to complete sets of Steam cards the 'real' way. I was asking about how to get the random booster packs to show up (I've played a lot of Civ V in the last few days without seeing one) and he didn't think there was any way to get them to show up. Eventually as people complete sets more booster packs get dished out randomly to people but playing the game more doesn't seem to impact your odds of hitting the lottery. In fact all you need to do is have played enough to get your base drops (which feels like an hour or two) and then log in to Steam every week. That's it. Leveling up (by completing sets) will increase your odds of getting a booster pack, as will earning all the base drops from more games.
How are you supposed to complete a set then? Trading or buying cards with other people. I've traded a few cards with Lino and my brother and have ended up trading away 3 of my 4 Civ V cards to get 3 FTL cards. I'm now only one away from that set, and apparently Robb has it. If only we were ever awake at the same time I could try to trade him for it! Collecting things and trading them can be interesting for sure. I used to collect hockey and Star Trek cards when I was a kid, after all, and this isn't that different. I also used to do a lot of Magic trading, but I wasn't a big fan. The problem there was the cards had drastically different values and you could easily get 'screwed' if you weren't paying attention. I've asserted to myself that all the Steam cards have the same value so if someone wants to trade a Civ V card for an FTL card I don't see any reason to not do it.
Other than trading with actual people you can go to the Steam card auction house and buy/sell your cards. Steam takes a cut of the sale, of course, like any good auction house. There was an achievement piece for using the marketplace so I sold one of my cards. A foil, because I couldn't see myself buying enough stuff during the Steam sale to get all the foils. I listed it for $1.75 and gained $1.53 when it sold. I was expecting to need to use that money to buy other cards when I got around to it but then my sister convinced me to buy Alan Wake and Steam used the $1.53 in my wallet to pay for part of that $3.99 charge. Woo! It looks like normal FTL cards are worth about 15 cents. Civ V cards around 12 cents. So I've been coming out marginally ahead by trading the way I have. Of course selling what I have and buying what I need would actually just result in Steam coming out ahead because of all the fees they'd collect along the way.
Lino commented about how he wasn't going to be buying or selling to complete sets, and I think that is an excellent stance to take. The problem is there's no real end to the amount of money you could spend. There are card sets for all kinds of games, and then foils too, and the system is designed such that you'll need to buy half of all the cards (or trade and only complete half of the sets) unless you get lots of booster lottery hits. It reminds me of the many 'Free 2 Play' debates, or of the Diablo III auction house drama. Collecting things and trading can be fun. Opening your wallet and just buying everything bypasses a lot of the fun and just gets you to the pointless end of the line. When it comes right down to it there isn't much point in collecting sets of Steam cards. The end result of having all the cards is you have all the cards. Hopefully you had fun along the way, and maybe you get a sense of fulfillment for having stuck with it and gotten stuff done. But that stuff goes away when you just buy them. All you get then is a sense of satisfaction that you have more money than other people. And while that seems to be a real thing for many people it's just not for me. I'm nothing like the Joneses, why would I want to keep up with them?