Walking up to the machine and bumping it will cost you one Penny, and roll the slots. You have no control over the results. It is possible to find Bombs (regular, troll, or 1+1 free), Hearts (half heart, full heart, soul heart or eternal heart, [Rebirth: Evil Heart]), Keys (normal or golden), Coins (penny, nickel, or dime), Pills (any color), Flies (Pretty Fly or black enemy fly), and A Dollar. Coins, hearts and bombs can all appear two at a time.
The symbols include Pills, bombs, hearts, keys, coins, flies, and dollar signs. Getting 3 flies will result in either Isaac getting the Pretty Fly orbital, or an Attack Fly being spawned from the machine. Getting 3 dollar signs (the symbol can't show up in other rolls, but the reels show it before the machine is destroyed) will make the machine self-destruct and spawn the A Dollar item, a collectible that sets your money to the maximum count of 99 cents.
If the Slot Machine is caught in an explosion of any kind, it will be destroyed, dropping several pick-ups such as bombs, coins, keys, pills, hearts, or even gold chests.
The probabilities in the table are the default. If you have Lucky Foot, every outcome except for nothing or the machine exploding becomes 1.4 times more common. If you are Eve or have Mom's Pearl or Mitre, it is more likely that your hearts will be soul hearts, as usual.
|Event||Chance of occurring||Notes|
|two coins||5.19%||7/135||Each individual coin follows the usual distribution, as above. So, two nickel or two dime are possible as well.|
|1 + 1 Free||0.588%||147/25000|
|Pill||4.67%||7/150||The type of pill is randomly chosen from among the six occurring in the current game.|
|Machine explodes||2.00%||1/50||A few items drop. This shoves you away from the machine and causes damage if you are standing very close to it.|
|Pretty Fly||1.56%||7/450||Does nothing if you already have 3 orbitals (Pretty Fly, Halo Of Flies, Cube of Meat, Ball of Bandages or Guardian Angel).|
|Dollar||0.467%||7/1500||An item which sets your money to 99¢. The machine explodes. Cannot be produced by the Portable Slot.|
- The delay between when the player gives the money to the slot machine and when it explodes to give A Dollar is shorter then when it does not explode (between when the player gives the money and when he recieves money, bomb, fly, key, hearts or nothing).
- When the machine explodes to produce the Dollar item, the Sad Onion can be briefly seen in its place for a few frames.