If your criteria were realistically attainable I wouldn't be typing this right now, I'd be living on my remote homestead as cut off from the world as I can get. Landwatch.com is a pretty good site to search for land. There are some sites that specialize in inexpensive land, can't recall any at the moment, but I think there was a thread here a long time ago that had some links, try searching.
I would suggest learning more about soils, remediating marginal land. Geoff Lawton focuses much of his work on making alkaline dry lands productive (which are the cheapest you'll find), but it is not some simple process you can just go do, you're going to have to learn some chemistry, soil science, do a bunch of research for desirable plants (and know what you're looking for), rotational grazing and animal husbandry play a role in the process, earthworks and water harvesting, it is not a simple easy fix.
Any cheap land you find is going to be cheap for a reason, and if you don't know how to work with the challenges that they present, you're pretty much wasting your time. Shit, so many people get incredibly fertile desirable land and still fuck that up. Take your time, really learn what you need to know. Good luck!
