Bus along the cliff or ferry across the bay. Both spectacular, both crowded in summer, both under €10. Bus is more dramatic (and nauseating). Ferry is faster.
Alilauro and Travelmar. The approach from sea — Positano's cascade of houses filling the cliff — is one of Italy's great arrivals. April–October.
The SS163 Amalfitana — hairpin turns, stunning views. Sit right for sea views. Standing room only in summer.
Ferry in summer — faster, better arrival. Bus in winter or for the cliff road experience.