He probably thought he was bidding on a 5 pack.
I did this a few weeks ago. Doing three things at once on the computer, saw a cigar that I think is mediocre, but it was cheap for a 5 pack, so I thought "why not, it's worth that," But it was a singles auction, so instead of a cheap 5 pack, I overpaid for a single I didn't even want that much.