Items sold for 15 pennies will have their price reduced to 7.
Pickups sold for 5 pennies will have their price reduced to 3. Red hearts, normally sold for 3 pennies, will have their price reduced to 2.
Multiple Steam Sales can be obtained via each of the normal drop methods, but doing so causes no effect.
Reduces all shop prices to 0 coins.
If Isaac has Restock, it is possible to collect an infinite supply of pickups/items. Extremely powerful when combined with Chaos.
Steam Sale will cause the Deals with the Devil not to convert the type of required heart automatically.
Items have a chance to be discounted further by random sales; for example, a discounted item originally costing 5 coins will then cost 2 coins instead of 3.
Diplopia: Can be used to create two Steam Sales, reducing the price of all items in the shop to 0.
Diplopia + Restock or Greed Mode: Restock will allow shop items to replenish indefinitely, so by having two Steam Sales by the method above, infinite items can be purchased. Be careful not to pick up Missing No., which will remove the Steam Sales and will likely replace many items with Breakfast.
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Items have a chance to be discounted further by random sales; for example, a discounted item originally costing 5 coins will then cost 2 coins instead of 3.
Diplopia: Can be used to create two Steam Sales, reducing the price of all items in the shop to 0.
Restock or Greed Mode: Restock will allow shop items to replenish indefinitely, so by having two Steam Sales by the method above, infinite items can be purchased. Be careful not to pick up 
Missing No., which will remove the Steam Sales and will likely replace many items with 
Breakfast.
The Binding of Isaac: Rebirth 
Achievements
Attributes
Bosses
Cards and Runes
Challenges
Chapters
Characters
Co-op
Items
Item pools
Monsters
Objects
Pickups
Pills
Rooms
Seeds
Transformations
Trinkets
