Interestingly, these same sorts of $200 deals are showing up on eBay, though not at quite the same bargain basement price. I did find a completed auction for $61 for a $200 card, though. Here's what Outdustry found out:
There are thousands of cards for sale at the same time. Choose one seller whose Taobao IM is online, talk to him a little bit, purchase his product and pay money to Taobao’s online payment system, Alipay, which supports most banks in China.You know, it's awfully tempting, but it is illegal, right? These vouchers have apparently been available for six months on Taobao. Interestingly, Yahoo holds a 40% stake in the site, and prices for these cards have dropped from around $47 to the current $2.60 as more sellers flooded the market.
All the seller actually sells is the gift voucher code which they send you directly through Taobao’s IM software. You can then redeem the card in your iTunes account.
Once successfully redeemed you then click ‘confirm’ and Alipay transfers your 18 RMB to the seller and you are free to start downloading.
The owner of the Taobao shop told us frankly that the gift card codes are created using key-generators. He also said that he paid money to use the hackers’ service.
Like I said, Apple is likely to change the algorithm, but they can't just rush into it without risking invalidating any legally purchased cards.