Formula which I was using to calculate price (((liter/100 km) * number of kilometers)/100) * 1.5
where liter / 100 km is 8.5 as much as I measured in my car, and 1.5 is the price of the gas
Bonn - Troisdorf - Ljubljana
Hostel Celica Art, from July 30th until August 2nd, 179,94 euros, 976 km = 82.96 liters = 124 euros
Ljubljana - Parma
Hotel Salus, August 2nd - August 3rd, 69 euros, 511 km = 43 liters = 65 euros
Parma - Genoa
The Hostel Genoa, 3rd - 4th August, 80 euros, 180 km = 15 liters = 23 euros
Genoa - Nice
Hôtel Du Centre, 4th - 5th August, 60 Euros, 192 km = 16 liters = 24 euros
Nice - Marseille
Hostel Sylvabelle, 5th - 6th August, 84 euros, 204 km = 17 liters = 26 euros
Marseille - Barcelona
Hostal Valls, 6th - 11th August, 440 euros, 507 km = 43 liters = 65 liters
Ibizza
Hostal Roca, 11th - 14th August, 192 euros
Back to Barcelona again
La Casa de Lilly, 14th - 15th August 180 euros (including 11th, 12th, 13th August for friends)
Barcelona - Novi Sad
1,989 km = 169 liters = 254 euros
Novi Sad - Bonn
1,416 km = 120 liters = 181 euro