few days ago i was taking apart my rocker panels,had no problems other then this clip that attaches to each end of the rocker panel next to the screw i been to two dealerships where they dont have it and was hopeing someone could identify this part.like i said it is the plastic clip right next to the screw on the end of the side rocker panels facing the wheel wells.thanks its a 01 monte ss
this pic is one thats broken cause it was impossibe to get out cause when installed the stem expandes out

 

The Parts department at the dealership shoiuld have no problem ordering this clip for you.

You can also try gmpartsdirect.com. But I do not know the exact name of the clip? Other then a push clip cause the center is pushed in to secure it.

 

The official name of this part is "retainer" I have these things in various locations on my car. I think they're all the same size. The list price is $0.81, but if you're lucky, they are discounted to as little as $0.48. See part #4

 

if you go to a local store like oreillys or something they should have a display of a whole bunch, its like 3 bucks for a little pack of 5 or something.

 

I don't think that it's a push style clip. I am pretty sure that they are called "plastic rivets".

They are fairly cheap. To set them in place, you pull the center pole out (right side) and it breaks off. Locking the rest in place.