Taking a C150 burning 8 USG per hour....
100LL at Naples, Florida - $29.28 or about €24 per hour
100LL at Weston = €1.75 per litre = €6.62 per USG, or about €53 per hour.
As Dutch says, utilisation then becomes an issue also where a Florida-based C150 might fly an average of 8-10 hours per day over the course of a year, a Weston-based C150 would be lucky to average 3 hours per day.