There are two kinds of "fashion math". The first is the good kind...where "cost per wear" equates to 10 cents an outing...or the coupon Gods align with the sale Gods to create something that is both just what you were looking for and about 80% off the regular price.

Then...there's the bad kind...where you desperately want, say, a couple of the over-sized tote bags created to celebrate 25 years of London Fashion Week (Preen's blue flowers and Charles Anastase's swan to be precise)...until you realize that the cost of shipping is exactly the same as the cost of the bags...