Buying Pokemon cards at anime conventions?

Has anyone ever done this before? If so, were the cards cheaper at all and did they have any deals? I'm planning to go to ACen on Saturday so I'm just wondering.

I've not seen any at any of the conventions I've been to, but based on the item markup I've noticed when compared to finding the items elsewhere, there's generally a bit of a markup.

Most I've done was buying cards from another con-goer, really.