Other than used, you are probably looking at Dealer only. Lower cost online dealers are:
GM Parts Direct: Your direct source for Genuine GM Parts
Monster Parts Online
Monster is usually better when considering total cost with shipping.
Another consideration to look into:
On some í00+ cars, the control arm bushings are liquid filled.
When customers complained about excessive vibration, GM had dealers replace the regular bushings with this type. (Iím not sure if any cars came off the line with these or not).
I have heard of failures on the liquid filled ones where the fluid leaks out and they become sloppy.
My non-liquid filled ones are still fine after 10+ years and 200k+ miles.