I admit, I'm a cheapskate.

I think my truck has 4 or 5 per side, and the one that's rusted away. Not sure how many were used. I probably need 4 or 5, not a dozen, but I guess I could pop for a dozen.
I did see that Bill's is in Canada, which makes shipping more expensive. I'm used to vendors who insist that on shipping stuff by second day air. I recently bought 5 tires, and they advertise free shipping, but not to Alaska. I put them in the shopping cart and it said shipping was $3000! I called and asked for a real shipping quote (as I had recently bought 4 tires for my wife's car, and the shipping cost was just over $100). They said shipping to Alaska was $600 per tire. I said I could drive down and pick them up for less. I wound up having them shipped (free) to a freight forwarder in Washington, who charged me $180 to ship them to their terminal in Anchorage.
I guess I overreacted, but USPS would charge less than $2 for the few ounces those clips would weigh. I realize someone has to put them in a package and get them to the shipper.
Like I said, I'm a cheapskate.
Andy, I think they keep the trim piece from collapsing.