The best website I have found for looking for real estate is www.landsofmissouri.com
Lands of Missouri , the site includes every property listed through any major and the majority of minor realtors as well as many for sale by owner properties. You can refine your search in many ways, location, acreage, price per acre, utilities, housing, etc.. You do have a tall order as you are asking for a lot at that price. I searched on that site and found 45 properties in Northern Missouri that were atleast two acres and have a house. Many of those properties may be too far south for you depending on where you are looking.
Missouri will have more freedom than Iowa and lower taxes in just about every comparable way. Iowa isn't a bad state, but Missouri has more freedom. A great way to compare states is the site
http://freedominthe50states.org/ 50 State Freedom. You can even run comparisons based on what laws are most likely to affect you. Overall Missouri is ranked #7 and Iowa is ranked #25. Iowa has one advantage to Missouri when it comes to laws in my opinion, Iowa doesn't have vehicle safety inspections which I consider a pain. There may be others, but overall Missouri is more free. Iowa is more liberal than Missouri, so you will get more money through state programs there than in Missouri. Some utilities in Missouri have rebates and such for energy efficient purchases, that will depend on what area you move to.