The Colt 1911 is one of the most formidable weapons ever produced for the United States military. Since its inception in the early 1900s, this powerful pistol has intrigued collectors and enthusiasts. They cannot be purchased from the government directly.
The fundamental problem is that a Colt sold by the government would be considered surplus material. All surplus materials directly sold by the government need to be demilitarized--meaning that they are no longer capable of inflicting harm. This may even entail a gun being turned into scrap metal.
If there are government surplus Colts, they are usually procured by private commercial sites or vendors. They may have access to government auctions where Colts are sold, but you, as the private consumer, do not. So your best bet for obtaining a Colt that saw military service is through one of these entities or through canvassing local firearms suppliers.
The prices offered by the aforementioned vendors will depend on a number of criteria. The first and most obvious is the condition of the weapon. However, collectors should be aware that Colt Firearms no longer produces this weapon so all "true Colts" can only be expected to appreciate in value over coming decades.