I didn't find much here on keys but my newly bought '03 only came with one key, and if that is lost, you are going spend lots of money at the dealer to replace the security module. Found new keys on Ebay for $13 and after it arrived I cut it to match. Followed the instructions at http://www.diy-time.com/automotive/toyota/toyota-sequoia-transponder-chip-key-programming/ under Method 2. Got it programmed the first try after Method 1 wouldn't work. Nobody should have only one key when they are this cheap.