When purchasing a product online, at the checkout I entered the wrong 3 digit security code for my card. Does anyone know what will happen? Will the transaction still be successful? Will I be charged? Will it even arrive?
The three (or four) digit number on the back of your card is called a CVV (or a CVC). In theory, being able to provide it means you have access to the physical card, and thus presumably are an authorized user. No one involved with credit card processing (the merchant, their processor, their bank, etc) is allowed to store it, so as to enforce that meaning.
What’s that mean for you? The merchant would have sent it to your bank, and been told “This is a valid card, and it can afford the purchase, but that CVV was wrong.” It’s then up to the merchant to decide if they’re willing to take the risk that you’re actually using a stolen card number (and thus they won’t get paid). Depending on the merchant, there can be lots of rules around this (transaction amount, whether you’re a repeat customer, etc), or they could just reject it.
If the merchant accepts the payment despite he “invalid CVV” warning, then it should go through and be charged as normal.