Cheap key to unlock vehicle

Do you have a vehicle that has one of those expensive micro chips embedded in the key? And because of that expense you have not purchased a spare in case of lock outs, well this cheap trick may save you some money. Just have a regular duplicate key made for about $1.00 from your original. Then if you lock yourself out with the original key inside, this key will unlock the door lock. Remember it will not start your car because there is no chip, but it will get you inside if locked out. It worked for my Tahoe and Grand Marquis. It should work for other vehicles too.