While not the most exciting option, the quickest least expensive would likely be a used travel trailer. Then adding insulation around it or putting up a garage (even the tent style) and insulating the garage. I had wanted to go the yurt route originally, but found it just was a lot more money and just for the shell, you still needed to fit it out with everything. A trailer however is a self contained unit, pretty much everything you need all ready and set up at the start. Add in some
solar and or wind to power it, a
water system to feed water to it, a composting toilet to not deal with black water, and a grey water system and your pretty much good to go.
This is the route I am going with my new
land. And while not a permanent housing solution, it will get me by for a few years while I start to build my house.
Later when you have a permanent structure you can
sell off the trailer, or convert it into guest housing, or an office, etc.. So it is a structure you can possible recoup your investment at least partially.