You can get one from ebay or maybe other seller websites. The key will still need to be programmed by a shop with a VIDA subscription (dealer or some indy shops) and it will not come with the emergency, embedded metal key to unlock the door if the car loses power.
My experience with keys from places besides the dealer says to bite the bullet, pay the dealer and be done with it. Those keys from the internet almost never work.
I have many stories of people trying to save money on things like this and end up paying more.
Exactly. You can try a cheap key from eBay but if the dealer tries to program it and it doesn't work, you're still on the hook for the software and labor. If they have one in stock they can program it at the same time for no extra cost though.