not quite sure I'd agree with "insignificant" - depends on how much it is driven. My 2nd Prius, that I owned from 2002-2011 consumed over £13,000 worth of unleaded. Had I kept my previous 1.8 auto Volvo V40 for that mileage it would have drunk nearer to £30k worth, and even the 1.0 Micra auto my partner had at the time would have consumed an extra £4,000 or so. Over the 160,000 miles or so, the depreciation, maintenance and other running costs were also tiny compared to very other car I've owned (adjusting for inflation), whether viewing it by mile or month.