So when I got my Cobalt, I drove away happy. Didnt realize at the time I only had one key. I had a spare made but it didnt work. Our cars use the Chevy PK3 circle plus Transponder keys. I called the dealer they want 49.99 per key. No way I was going to pay 50$ a key. I went online and was able to find this guy on ebay. I got them for 9$ plus shipping per key.

Step One: Order key from http://stores.ebay.com/Transponder-island He was the best price I could find everyone else is like 15$ and up.

Step Two: Take the uncut keys to your local GM dealer to have them cut(mine didnt charge me to cut my keys), or go to a local walmart /homedepot.

Step Three: After your new key has been cut, place the known good working key into the ignition. Start the Car, then turn the car off and remove the good key.

Step Four: Place the new key into the ignition within 15 seconds of removing the old key. Turn the key to on but do not start the car. The security Light will come on on the bottom right corner of your dash. Do not move the key till this light turns off. Once this turns off remove the key from the Ignition.

You now have a spare key that cost you a Quarter of what GM would charge.