One of the few areas American cars got right. 2001 Taurus? Key with chip, $9. Cut, $2 at ACE. Turn car on with key 1. Turn off, turn car on with key 2 within 10 seconds. Now turn off, put in new (cut) key, car recognizes new chip, authorizes add based on other two successful authorizations, and bam, new key works.
Only thing that sucks is it's still a 2001 Taurus