It is not too hard to answer this question.

Simply put, 3 minutes is all it takes for all the best 

stuff (reasonalbely priced) to sell out, also all the 

bargains will be gone in 3 minutes as soon as the door 

opens, of course there will still be plenty of high quality

cels left after a few hours from opening, but the price

will be very high on these cels.

This is a common sense when attend any conventions