You can also exchange its last resource for your last resource. That usually works out pretty well, and I've done it before to gain some influence of CS.
Really? My experience has always been that the AI values my last resource as any other resource, but values its own last resource very highly. Either way, I'd say my overarching point of East India <<<< Bazaar still stands since some people were drawing or asking about that comparison. Since with a Bazaar in that same situation you wouldn't be trading away your last copy in the first place.