The consistent hype around TCG's like Pokemon on MTG can't be understated, but spending real money on packs has done some hurt to mine and I'm sure many others wallets. I believe Torn already has the established and active item market to support something like that within the game. Picture this: a supply pack item, a booster pack for Torn: TCG (a more fun name or totally different IP may be better). Within the booster pack, you'll get anywhere from 1-5 cards, and the players will decide what they're worth in the item market (though rarity will be determined by an explicitly stated rarity system).
Down the road, it could evolve into an actually playable TCG, with money to be won a la the casino, or even something as big as tournaments! New expansion packs can release once or twice a year with updates, and a resurgence in activity will be seen, reducing the price of the old packs and drastically increasing the price of the new.
Thoughts?