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.