We rented a camper van with Rent.is for two people for 6 days in Iceland. It was a small one but was amazingly well equipped, with everything you need to cook and eat, and with a heater working on a second battery, which was great for the cold nights. We chose the premium insurance to be able to pay with a debit card instead of a credit card. They picked us up on the airport and drove us to the offices where we picked up our van, starting our roadtrip through the ring road right away – we returned it at the same place before our return flight.
The roadtrip through Iceland was an amazing experience, and I recommend 100% doing it by renting a van – the best way to discover Iceland!