I also just spent the better part of a half hour trying to figure out what this one guy wanted, and I knew I was right from the get go, but he was adamant I was wrong. He wanted the Secret Invasion Saga, which was a free giveaway from Marvel.
Now I knew what this was and told him what it was, but he was sure it wasn't free. And of course I ran out, so I couldn't just show him. So we went through the distributor (CURSE YOU, DIAMOND), and no luck finding a Secret Invasion Saga that actually cost money. EVEN THOUGH IT WAS THE EXACT IMAGE AND DESCRIPTION.
Then we go through the Marvel website, and no luck.
Then we go through Wikipedia, and no luck.
Then I leave him to help people, but I let him browse online to see if he can find it. He calls me up saying he found it on the Marvel site. I go and look. AND IT'S THE FREE COMIC I SHOWED HIM BEFORE.