I am lucky enough to be traveling in Barcelona now (ostensibly for work). When we looked into taking the cable car to the top of Montjuic, I noticed the prices as posted below. Notice the bundling. The second ride is much less expensive than the first. But the same prices schedule was posted at the top of the hill as the bottom. Since the demand for traveling up is much greater than the demand for traveling down, I hoped to see price discrimination based on direction of travel.