Why does an Olé cake cost less than a Leo?

Why does a loaf of bread cost €2 at one bakery and €3 at another? Or why do you pay more than double for a Leo cake than for the identical Olé cake? Economist Tom Kuppens (UHasselt and VUB) explains price-setting strategies as an elegant interplay between supply and demand and also gives away that behind your bonus card from Carrefour, there is more than you think...