How much does it cost to drive the Iceland circle? And the full circle in particular?
The only road toll you will find is in the South West and is at the entrance to a tunnel that spans the Hvalfjörður fjord. It will cost you 1.300 ISK per vehicle to use the tunnel.
The fuel price changes a lot so it's better to check out the current prices and do your own calculations based on current fuel prices: GSMbensin.is
When this was written, August 31st, 2017, the fuel price was:
185 ISK per liter / 6.7 USD per gallon, on average.
If you take a mid-sized camper, like the Easy Fun and do a full circle (including stops and detours), you'll drive somewhere between 1350 and 1500 Km or approx 890 Miles.
As we do the calculation, we use the most expensive fuel stations, suppose 1500Km, and highest consumption and get something around:
23.500 ISK / 225 USD / 190 EUR in driving costs.
Want to do the math with the current fuel prices?
0.08 (fuel consumption per km) * 1500 (km driven) * x (Diesel fuel prices in Iceland)