We figured that as long was we were putting together a list of the thriftiest crossover SUVs, that you might wonder which utility vehicle’s annual fuel bill is the most expensive. That would be the Geländewagen. Even the hyper-powerful and hyper-pricey Mercedes SLR McLaren is $300 lighter on your wallet when it comes to gasoline. It looks like a military vehicle and guzzles gas like the Pentagon guzzles tax dollars.