The best fuel deals are normally where the vehicle is collected and returned full. The hirer is responsible for paying for their fuel usage during the rental period. Read more about the fuel policies.
If your quote has CDW Insurance is there an excess, and if so how much. Read more about the CDW Insurance.
Many of the cheaper offers may be from companies with premises which are not located within the Faro Airport compound. A shuttle bus service will be provided. If cost is important, consider renting a vehicle from a smaller local company with their own off-site offices.
If your flight arrives late at night there will probably be “out of hours” charges. Consider getting an earlier flight if this is possible.
Larger vehicles are generally more expensive, especially 7 and 9 seaters which can cost 2 or 3 times as much as a small car. Consider hiring 2 smaller cars if you are travelling as a group.