I paid 750 for mine and I think I may have paid to much. Start at 550 and go from there with your haggle. Just my opinion though.
I am presuming excellent condition though.
For what it's worth, I have a Colt Combat Commander Series 70 that was built in the late 70's. I had some mods done to it by a top-flight smith: sights, accurizing etc. It's extremely reliable. I wouldn't sell it for less than $1000.
how about a Colt Lightweight Commander in mint
condition, in the original box with all paper work.
S/N = CLW 25xx? The very firm price of $1200.00
might get you a sneak peek.
I bought mine a few years ago for $800. But it came with 7-8 mags and had been moderately customized. It is by far my favorite pistol and will NEVER be sold. Hmm, I guess that doesn't really answer your question, but whatever you pay will be worth it in the end LAter.