In 2007, a rocket propelled grenade launcher was being sold on the black market in in Iraq for $100. Grenades for the launder were being sold to insurgents for $50 per grenade.
The Russian model of the Ak-47 was being sold for close to $500 in 2007. Back in 2003, the gun was being sold for $50.
Source: Ahmed Rasheed and Ross Colvin, ” Iraqi police selling weapons on black market,” Reuters, February 5, 2007.