I found the cheapest way to get a key is through one of the online dealers that sells parts over the internet and mails them to you. I actually used one in my own town and it was a lot cheaper getting it through the mail than going down to the parts counter at the same dealer. All you do is supply the VIN and prove you are the owner and they send you a key cut with transponder matched to your car and you can program it in the car. As far as the lost key I guess its a personal decision on the risk of someone using it on your car. I don't know if the dealer can furnish a new key that would program car differently so old key would no longer work. OF course you would have to reprogram the existing key, too.