Geo targeted domains are good from an seo standpoint because of the fact that they generally bring in very targeted traffic. Which means, the users that end up on the site are more likely to respond to any call-to-action because they didn't just land there by chance, they are looking for a specific service in a specific location and found it.
The problem with your domain, is that the "free" keyword seems misleading, while leaving out "houses". Unless someone is actually giving away free prairie houses, this would be problematic.
Kansasprairiehouses.com or even kansasprairielistings.com would be ideal, though.
"Free" is a keyword you definitely want to stay away from. While it might seem like an attractive way to get more traffic, it's all garbage traffic from ppl who will close the tab the second they realize they are not getting whatever you are selling for free.
The idea with GEO domains is that you should buy those that have many potential end-users and contact them one by one, by email and / or phone. The domain is better in quality when GEO stands before the keyword and not after it. The right price to ask when contacting people directly is usually between $200 and $500, although it can go higher for durable goods like real estate or cars. Selling such domains here on forum would be a bad idea, since by experience it is hard to sell GEO to domainers above the regfee. However, reasonable profits can be made with GEO, especially if you are from the US and are good at speaking to local businessess.