Shops sell various items in exchange for pennies. Shops start at level 0 and only sell 2 consumables. They can be upgraded through the Donation Machine, which can be commonly found in the shops and sometimes in an Arcade. Each level increase adds to the shop's background and affects how many items are available.

Shops can sell Hearts for 3 pennies. They can also sell Soul Hearts, Bombs, Keys, Battery Charges, Pills, and Tarot Cards for 5 pennies each.

- One of the biggest draws of the shop are the items that they'll sell for 15 pennies. A list of items that can be sold can be found here.

- Randomly, the prices will be cheaper and in red. Hearts will be 2 pennies, other pickups will be 3 pennies, and the items will be 7 pennies. The Steam Sale item always makes all prices cheaper.

- Using a Credit Card in the shop will make all items available for free.

- Having the trinket Store Credit will cause all items to be available for $0 but will be consumed upon one purchase.

- Using the Rune of Jera creates a free copy of all pickups, even if you haven't purchased them.

- You must use a key to open the shop. The "Curse of the Maze" will allow the chance of entry without spending of a key. However, its door is the same as the Library, and if you have no Items that make it - otherwise, its symbol will be a key in the minimap.

- Shops also have a chance of being replaced by a miniboss room containing Greed or Super Greed. The Shop can never spawn next to the starting room of the floor (except for Basement/Cellar), so it is a good way to tell if it is a library, or not.