Check for extra charges over & above quoted tariff for the following & the small print:

• Mileage limit & excess charges.
  
• Additional drivers.
  
• If required, cost of leaving car at another location to that where car was collected.
  
• Additional cost of fuel if you return the car without a full tank of petrol.
  
• Car accessories such as roof box, child seat, snow tyres or chains.
  
• Insurances:
  
  • Collision damage waiver (CDW) which limits your liability to the excess. You may pay extra to have no excess in the event of an accident, although this can be expensive.
    
  • Theft insurance protects you in the event that the car is stolen
    
  • Supplementary third party insurance is usually only required outside Europe, as sufficient cover is provided automatically.
    
  • Personal insurance covers possessions, injury & death. Often you will already have this cover from your travel insurance, or say, credit card purchases.
    
    

It is usually advisable to book ahead in the UK or online when abroad as it is usually significantly cheaper than renting from a local office overseas.