It is not possible to reprogram a used Smartkey, correct?

It is not possible to reprogram a used Smartkey from one vehicle to another, correct? Even if I find a "new" key on eBay or something, will that work? I thought I saw someone saying to program these keys you put it in the ignition and leave it for however long, but that's only for a new key. Then I call the dealer parts department and they tell me a new key will come completely ready to go, but then the service department tells me it needs to be programmed. So which is it? (And I don't want to hear about how the dealer is trying to screw everyone). Can I save myself some money or am I just going to have to deal with it?
I'm not sure about new keys, but I believe it needs to be programmed before you can use it.

If you just want the new key... Go on ebay buy a used key and switch the parts out inside easy as cake

If you just want the new key... Go on ebay buy a used key and switch the parts out inside easy as cake
I already have the new style key, I just want a second key in case something happens to the only key I have.



