The top image is not the snowmobile in the ad, but it looks the same and the images from the ad are tiny:
The odd vehicle you see here is a 1968 Bolens Diablo Rouge 502. It is an antique snowmobile. Snowmobiles of this era are often a bit weird, as the 50's, 60's and earlier were a bit like the early days of the automobile for snowmobiles. These were a new type of machine, and there was no specific idea yet of what a snowmobile should be like. So sometimes when looking at old snowmobiles, you’ll see contraptions that don’t look too far removed from modern snowmobiles, and other times you’ll come across something like this:
Basically, the motor, clutch, tracks, gas, and everything are all in the front module, and then this module pulls you around on a little sled while you hold onto some handlebars attached to the front module. So you’re controlling the tractor while sitting on the trailer. Seems simple enough.
The most desirable Bolens Diablo Rouge is the 503, which featured an electric starter, a bigger engine, and a quieter muffler. This one, however, is the more common 502, which was the workhorse of the three Diablo Rouge models. Still an interesting old snow machine, though. The ad for this one doesn’t give a lot of information, though it does say it has been restored. It also says the price is $3,700. So... Is the idea of putting along on a sled behind this sturdy, shiny, red devil tempting enough for the price, or would you rather just use snowshoes?