Buyers shopping for a 2016 Mercedes-Benz S550 might get sticker shock upon learning exactly how much upgrading to the S550e plug-in hybrid variant will cost... because it won't cost a dime.

Opening bids for either the gasoline or gasoline-electric hybrid version of the uber-lux sedan will begin at $95,325, including destination. It's a surprising move from the German giant, which recently announced that prices for its M-Class-replacing GLE jump by as much as $3,000.

To find a Mercedes-Benz where the green credentials didn't come with a premium, you have to go back to the S400 Hybrid, which was actually cheaper than its S brethren.

2016 BMW X5 xDrive40e

2016 BMW X5 xDrive40e

But we wouldn't imagine this is the start of a trend, as BMW went the traditional pricing route with its forthcoming X5 xDrive40e plug-in hybrid. Going green in the X5 means a sticker price of $63,095, making it a whopping $8,200 more than the line's point of entry, and second only to the eight-pot X5 xDrive50i—MSRP: $71,695—in terms of cost.

Of course, it's worth mentioning even that premium pales in comparison to the nearly $20,000 price jump buyers will face with Volvo's range-topping 2016 XC90 T8 ‘Twin Engine' plug-in. The Swedish maker's flagship will start at $69,095. 

How the numbers will influence sales remains to be seen. But it's clear that most of the time, it ain't easy being green. 

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