Narantuul
The huge open-air market, Narantuul "The Black Market" in Ulaanbaatar offers the lowest prices on just about anything you could want. Be very careful of the many pickpockets and even attackers there. This can be a great place to get a good pair of riding boots. You can opt for a variety of Mongolian styles, from fancy to the more practical, or even get a good set of Russian style boots.