When it comes to Pokemon TCG, tradeable packs are like the currency in this game. You use packs to buy other cards, or even trade them for other packs. Each card and each pack vary according to value, i.e. some packs and cards are more valuable than others. To understand how the trade mechanics work, each pack has a certain value ranging from 0.5 to even 20.

For example, Flashfire has a value of 0.5, Roaring Skies has a value of 1.0 and Dark Explorers has a value of 1.5 packs. What this means is that every 2 Flashfire packs is equal to 1 Roaring Skies pack and 3 Roaring Skies packs are equal to 2 Dark Explorers packs.

Each card has a certain value as well. For example, EX cards like Malamar EX is worth 3 packs (value of 3.0) and Lucario EX is worth 4 packs (value of 4.0). However, there are two types of EX cards, Full Art and Regular Art. Full Art cards tend to be worth more than Regular Art cards. For example, Full Art Lucario EX is worth 7 cards while Regular Art Lucario EX is worth 4 packs.

These pack values can be found on the Pokemon TCG Forums – there are many trading companies with different prices for different cards and different packs. You may also order from these trading companies directly if there is any card you need. Here is the link for you to check out: http://forums.pokemontcg.com/forum/33-in-game-item-exchange/