You will take benefit from this offer only if: you buy articles of the same category and the same unit price.
a small pleated hair slide + a small starfish hair slide = same unit price (3.50€) + same category (small hair slide)
= decreasing price (6.50 € instead of 7 €).
Other examples :
a bowling bag + a tote bag-medium size = same unit price (29€) + same category (bag)= decreasing price (57€ instead of 58€)
NEW IN 2013: if you add a third article, it still working!
However: a bowling bag (29€) + a handbag (27€) = different unit prices therefore there is no decreasing prices.