Car door lock, 2004 Chevy Aveo

I have a 2004 Chevy Aveo. It does not have power locks, and the driver’s door must be locked from the outside. When I left work today, I unlocked the door and drove home as usual. When I got out of the car and put my key to the door, something was missing. The metal part where the key goes into was not there! Basically there is an empty hole in my door handle where the lock was before. On closer inspection, it looks as if the metal piece has fallen inside the door. Nothing unusual happened on my way home, so I’m baffled! How did this happen, and how can I fix it?

A u-shaped clip keeps the door lock in place. The clip slipped out, or broke. A mechanic, or an auto body shop, can fix it for you.

same thing happened on my '06 Aveo. I took it to Merit Chevrolet in Maplewood, MN, and was told I need to order a new door handle, key and lock cylinder. The total estimated cost for the repair, with new door handle, key and lock cylinder, was about $250. How much should it cost to just take the door apart, reattach the key cylinder, and put the door back together? Where can I get the repair done?