Anyone do this before? I came across cardhub.com, and immediately when searching amazon, I found a $200 offered at $110. Sounds too good to be true, and it seems like the site doesn't serve as a broker, since they say:
We recommend that you avoid purchasing gift cards from people you don't know, unless you can meet them in a public place. If you would like to proceed anyway, please click the message button to contact the seller. CardHub does not guarantee third-party transactions.
A friend has sold gift cards before, but I don't know anyone who has purchased.