Re: How to program your own key. SAVE $$$
If your key (with fob) works to start and run the car, you are golden! The difficult and expensive to replace piece is an RFID-type transponder chip glued into the fob which has to interact with an antenna right behind the key cylinder bezel to let the motor run. This chip is NOT connected with, does not use, the circuit board and battery inside the fob which control the lock / unlock functions.
To get the lock / unlock / alarm functions working you can follow a procedure listed in the owner's manual. (OR pay a dealership $100 or so.) As in an earlier post: "Used the instructions in the manual to reprogram the fob (press the lock or unlock button on the fob twice and then insert the key into the ignition and the on position within 30 seconds)."