According to research by website iCarhireinsurance.com, hiring a compact car with Budget in Tenerife during Easter (13-20 April) costs £116 for a week. However, once extra items at the rental desk are included, the price soars to £527, more than four times higher.

The most expensive add on is £92 for sat nav hire, while adding an extra driver costs £61 and a child’s car seat will set you back £74. Other ‘extras’ include £86 for Super Damage Waiver, £67 for Super Theft Waiver, and £31 for Tyre and Windscreen cover.

The study compared the prices of six rental companies (Avis, Budget, Sixt, Europcar, Enterprise and Hertz) in five popular Easter destinations (Tenerife, Nice, Barcelona, Milan and Larnaca).

The average cost of adding an extra driver, across the five destinations, was £57, with Hertz in Barcelona the most expensive place, charging £97, while in Larnaca, Enterprise only charged £18.

The most expensive place to rent a child seat is in Milan with Hertz charging £116 for the week’s hire, while in Tenerife, Avis only charges £21, a difference of £95. The average price across the study was £59.

The average cost of hiring a sat nav was £80, but it costs as much as £121 with Hertz in Barcelona, while Avis in Tenerife charges only £34, a difference of £87.

Ernesto Suarez, founder and CEO of iCarhireinsurance.com, said: “When booking a hire car it is crucial that you know what extras you are going to need, and how much they are going to cost you, so you can accurately compare prices.”

How to avoid sky-high extra charges

Here are some useful tips from TravelSupermarket to keep your car hire bill down:

Avoid the ‘full – empty’ fuel policy

This is where you pay upfront for a tank of petrol and can return it empty. You may be charged an inflated price for the petrol and can end up paying for fuel you haven’t used.

Instead, opt for a full – full fuel policy which allows you to return the car with the same amount of fuel at pick up. Before returning it, don’t forget to fill your tank to the same level as when you collected it.

Choose an agreement with unlimited mileage

This ensures you won’t be charged for excess mileage.

Do you need extra insurance? 

Car hire companies will charge you extra for insurances including personal accident insurance but you might not need it.

You’re likely to be covered for personal accident insurance (this pays out if you are severely injured or die in an accident in a hired car) through your travel insurance policy or through the credit card that you used to pay for the rental but it’s important to check before you go away.

If you’re travelling internationally, call your credit card company to see if your destination is covered.

Buy your own excess policy

Buy a car hire excess policy online in advance of your holiday. If you buy an excess/damage waiver policy, online in advance of your holiday, it will only cost a few pounds a day. If you buy it at the rental desk, it can add around £20+ extra a day to the cost of the rental.

If you take more than one car rental trip a year, consider whether it’s worth getting an annual policy which costs only a little bit more but is cheaper than buying it for two single trips.

Bring your own extras

Save money by bringing your own sat nav and child seat. Check if your airline allows a car seat for free – many do. But even with baggage restrictions, it is likely to be cheaper to take a child seat with you than hiring one from the car firm.