Black market
From Halopedia, the Halo wiki
Black Market Bazaars are locations where illegal products can be handled on the black market by either pirates or rebels of the United Rebel Front, although the fact that URF rebels attend these bazaars is not certain. A black market bazaar was spotted in November of 2525 near the Roosevelt Military Base, which was taken down by Blue Team. Such "Black Market Bazaars" were known to sell Covenant weaponry for human uses.
