The Merchant of Menace is your one-stop shop for almost anything you need to take down those pesky North Koreans, from airstrikes to vehicles and even supply drops. It is set up by the Russian Mafia and unlocks after finishing Foothold. The items will be unlocked as you complete contracts, as well as when you collect Blueprints and National Treasures. The prices on the items seem to vary based on your standing with the Mafia, so an average of those prices will be listed below.
There are three categories you can purchase, which are vehicles, supplies, and airstrikes. When you access the store and pick an item, it will be put on your support menu in the form of a smoke grenade. Tossing this smoke grenade will bring in a helicopter that drops off what you bought. In the case of vehicles and supplies, you aren't technically charged until the item is dropped off, although airstrikes are charged as soon as you use it.