Ok, here's how I see it regarding the initial price of $79.95:

Dan has X amount of knives, he opens the store on Sunday afternoon. He's packing up and moving out on Tuesday, so that's the last possible time the knives will be at that price...BUT...that's only if there are any left.

So, how long the price lasted was up to us in a way. Had we all taken our sweet time the price would have been good 'til Tuesday (hey, that was a band right?), as it happened we all gorged ourselves in a matter of minutes.

Sure, he could have made a bajillion of them and in so doing guaranteed enough for all, but who knows how long that would take to produce? I surely don't.