GunBroker "sold" prices are market prices. A price above or below those prices would be "crazy." You will have to be "crazy lucky" to find an example for substantially less.
In my personal opinion, a Colt Model O Commander is needlessly big and heavy, and of limited magazine capacity, for the little 9x19 cartridge. If one is going to go down to the 9x19 cartridge, then an appropriately small and light pistol with greater magazine capacity would seem the more logical choice. My personal choice for a 9x19 carry pistol is a Kel-Tec P11, which is about the size (but thinner) and weight loaded of a Colt Cobra, and has a cartridge capacity of 10+1.
If you still want a Commander, then get ready to pay market price now, or hope for a "crazy" (low-priced) example to appear - sometime.