It is all about luck and a lot of patience.

Went through this with CC stores closing in the earlier round late last year. I was able to get two good deals - a flash for my Olympus at roughly 60% off and a 8GB Extreme III CF card for about $36. But I probably went into the store over a dozen times between when the liquidation "sale" started and their last day (I live around the corner from one of the stores).

Went the last day and it was all the leftovers. And they wanted to go home. A guy would go over to a section and say "All ____ are now $1". Heard this for batteries. But all that were left were 9V and D.