Ad verbiage for the allegedly 3250 running watts generator states "engine run time of 10 hours at 50% on a common 20Lb (gas grill type) cylinder". So that's under $2 for 1.625kWh, which is roughly the power draw for recharging the Nissan Leaf in question, which takes 20 hours - costing upwards of $40. More to your point, that's about $1.23/kWh. Not cheap, but a 10x markup is appropriate and acceptable for emergency needs.