The city of Concordia, Kansas operates Airport Park Campground, located on the south side of town: "The scenic and wooded camping area includes 12 pads with water and electric hookups and a dump station. Several other pads are available without utility hookups, and the site is ideal for tents. Restroom facilities are located onsite. A picnic shelter, storm shelter, pay phone, and playground are also adjacent to the campground."
Airport Park offers both RV and tent camping, and is a "fee-by-donation" site that works on the honor system, so you pay whatever amount you feel is fair.