After being admitted to the Union in 1820 as a slave state and for the first seventeen years of its existence, this is what that mountainous state immediately to the east of Kansas looked like.
In 1837, Congress paid $7,500 for 3,150 square miles of land from two nations, the Ioway and the Sac and Fox, to add to Missouri's northwest corner. This purchase would later cause the state of Kansas to be admitted to the Union in the shape of a parallelogram with the northeast part nibbled off.
The sale required the two tribes to move west to Kanzas, which was then part of Indian Territory. Both tribes still have a reservation in Kansas.
Purchase price was $7,500 or about .0037 cents per acre--a much better deal than the two cents per acre Seward paid to Russia for Alaska.
(http://i941.photobucket.com/albums/ad256/waldoegray/Missouri_zpse5970a0a.png) (http://s941.photobucket.com/user/waldoegray/media/Missouri_zpse5970a0a.png.html)