This paper/presentation aims at introducing the reasons wh y switching from the current flat-rate Internet pricing to another schem e is required, at briefly classifying the existing propositions, and at highlightin g the challenges that still have to be tackled in the area. Pricing has indeed become a hot topic in the networking literature in order to control congestion, diffe rentiate services among users and somehow fairly share the resource, but is still the subject of debate about how, and even if, it should be implemented