Black Market

Black Markets are unique shops that can be accessed through a Crawl Space. Black Markets are 2 rooms wide. The left side of the Black Market contains a door back to the crawlspace and a trapdoor or beam of light to the next floor (including the or, even if they haven't been unlocked yet). The center of the room contains several items from the Shop pool that can all be bought for 1 Red Heart container. Although these will not be Devil Room items, they still count as Devil deals for Angel Room generation and unlocking. This is no longer the case, and Isaac can buy items from the Black Market without affecting the spawn chances of Angel rooms. The rest of the room will be strewn about with shopkeepers, pickups, and various beggars and machines.

Starting in patch version 1.03, Telepills and have a very small chance to teleport you to the Black Market, but there will be no door leading to a Crawl Space. This means that the player will be forced to take the trapdoor/beam of light if they don't have any item to teleport again, like in an I AM ERROR Room.

Variations
The following room maps were made using Basement Renovator for cleaner viewing; note that all Urns you see will be Skulls when encountered in-game. Additionally, the door to the crawlspace will close if there are enemies in the room, but the trapdoor will always be open.

Seeds
ZH2A NT12 (The Cellar II, large room on the top left of the map, Tinted Rock on the middle-right side of the room) ZJTC L4DS (First floor 1 room to the right, Rock in the middle of the room) S3B9 KPMG (Bedroom adjacent to spawn, Treasure Room adjacent to spawn contains Pyro) RS1V ZOLD (For Greed mode, the Rock on the top left of the Shop on the first floor, and there is also a in Silver Treasure Room which gives you Bombs to break it) 3PKW XC9M (Right before boss room by the tinted rock)