They stopped making the HHR in 2011 so you can only find them used. I don't know where you are located but Mayse Auto in Aurora, MO buys all of them they can find from rental car companies and GM company cars. When we bought ours they ONLY had about 35! They usually keep between 45 and 60. They were great to deal with and we have towed ours about 4000 miles.
We had a problem with the battery discharging and even put in a switch to keep from this happening, but it did'nt help. I am told the HHR is wired differently from most cars and I am still working on this problem. Now we use it as a reason to stop every couple of hours and get out and walk around and start the car and let it run.
