how to get trading cards

[MinecraftBroJang]

after buying the game a few months ago, i got some trading cards. Just now, i've taken an interest in trading and the market system. i got four starter trading cards, but when i went to trade, i notice my friend had an underworld trading card. i dont have it, though, and i want it. how can i collect it?

[Bolt]

Offer him a "Trade offer", and offer other Item (Another trading card or anything for the same value in your inventory)

EDIT:
See this...
http://steamcommunity.com/tradingcards/faq/

http://steamcommunity.com/tradingcards

[MinecraftBroJang]

can i get trading cards by playing the game, though?

[FuzzButtHead]

in every game, you can only get 4 card drops for some reason

[Bolt]

Yes, by playing Terraria you get a Limited amount of card drops.

Each game has a limited card drop. (Equal to the half of cards needed to complete the set).

After you got all your drops (Terraria gives you 5, I think), you complete the rest of the set by trading buying it on Market.

[hachimi]

Or opening booster packs, earn duplicates of the half set, then scrap them for gems, then turn the gems into booster packs

[Overlord]

yes

[George Droyd]

ive played terraria for about 42 hours but i havent gotten any card. is that a glitch?

[Fumo Bnnuy n Frends]

keep playing or booster packs

tbh you save more money from just buying them from the market or asking friends / trading with people.

[Rajida Viper]

Remember that you have to buy the game to earn cards. If you're playing the game from a friend's library, you won't earn cards.

[George Droyd]

i bought terraria and ive played it for 50 hours now. i bought it myself and i didnt get it gifted.