I like the subtle reply of.."Good luck finding that,you'll never find one as I've been looking along time for one too".
In one sentence,they've managed to not only dash your hopes,but to also imply they too are a buyer of said item,and to insinuate to anyone with said item for sale to quote you a high price as it's hard to find and there is more then one person interested in it here too.

Collecting Vintage Sunoco