Vesuvius is the cheaper option. Entry fees are low, and it’s easy to reach by train from Naples (Circumvesuviana + shuttle). No need for expensive gear or guides.
Etna costs more. The base is far from major cities, and if you want to go beyond the lower trails, you’ll need to pay for a cable car and 4x4 truck, or book a guided hike.
➡️ Winner: Vesuvius for affordability.