I have a basic philosophy when it comes to buying multiples. If it is a figure I really want multiples of (ie Army Builders) I try to leave at least half of what I find on the pegs.I've been on runs in the past during the early Saga years (the elusive Dooku stage) and have run into scalpers or people who were just flat out buying 3 or 4 multiples of very HTF figures just because they could.
For example, if I find a store with 4 Animated Clone Wars Clone Troopers I may buy 1 or 2 to open, and in doing so I will look for the least desirable package, because I know that I will be opening it. If the same store has 3 I will only buy 1, but if they only have 1 and I already have the first (MOMC) one I need I will leave it. Does that make sense? I just try to be courteous.
I'm glad to hear you are all trying to help each other out. I can't tell you how many time posters here have helped me score, say...the new Unleashed Clone Trooper, or some other such goodie.