So, are you looking for a particular box to be on sale? Otherwise I would consider 10% off to be too small to bother. In another thread several of us were discussing the 60-80% off deal of some craftsman intermediate boxes that a number of us took advantage of.
Odd thing is, Sears is "training" us to buy only when items are heavily discounted. I now find that I won't buy a tool at Sears unless (1) I absolutely have to have it right now, or (2) it's at least 50% off. Good for me, bad for Sears in the short term. Bad for me and bad for Sears in the long term if they go under. BUT, we live in a culture where both consumer and corporation only think a week (or less) into the future.
"Let us eat, drink, and buy tools, for tomorrow we may die!"