Faro is located about 60Km away from Spainish border, around 50 minutes driving by car. The closest Andaluzian cities are Huelva (114 km) and Seville (200 km).
The EVA Transports provides daily connections between Seville and Faro. The route can vary from 3h to 4h, depending on the service selected.
Gas costs vary between Spain and Portugal, from 1.35€/1.40€ in Spain to 1.50€/1.60€ in Portugal. If you are coming to Portugal from Huelva, you will have electronic toll in A22 (around 7€).