Personally I really like Cobras and have owned a few over the years. For those readers not familiar with these gems it's a 6-shot revolver built on a D-frame (same as the Detective Special) but out of aluminum alloy. And the finish on both the alloy and steel parts are typical Colt and beautifully done.
Unfortunately, these never really became popular, so I never saw any collector market for them. So in terms of value, I'd have to say $250, $300 max.
The last one I had I traded to a coworker for a mint 1918 DWM Luger. He wanted a pistol that his wife could carry, and I wanted the Luger. I thought it was a great deal because I only paid $225 for the Cobra, and he thought it was a great deal because he paid $150 for the Luger. It was a win-win situation.
Unfortunately that was my last Cobra. But if I ever run into another one for a good price I'd probably snatch it up.