Borderlands 2

You need to buy them through the market or get them through card drops. There are various sites that allow you trade for cards, just google it.

Just sell some of your cards from other games and use that money to buy them in the market, that's what I usually do..

There's just 3 drops in Borderlands. The rest you get from trading.

I would've traded you, but you don't have any cards i need. I mean, you do have the cards I need, but then you wouldn't have your complete deck if you traded me those :P

Funny I got all three of those cards the other day for two of my Skyrim cards :p

Sold it in market so can't help you.