Nothing - when I finally got to leave the car at the rental place.
No signs, employees could not be distinguished from the people on the street - no badges, shirts. Instructions inadequate - you don't drop off at the budget office, you drop off on the other corner of the building which can take up to 30 mins to get to by car because it's Napoli. Then, the process jumped from $268 (which was on the form at check in, and in line with what was promised on kayak) to 298 €!! That's $340. And kayak has no customer support and budget won't address this problem so I guess I will issue a charge back with my credit card company.