When it comes to used guns, Strafor Gott pointed out that the metal-framed S&W autos are good value, especially the 3rd-generation (4-digit) models. I have some 1st-Generation models that are extremely good as well. The quickie photo below shows both an S&W and the Beretta 92FS. The S&W pistol was purchased for under $400.
Beretta 92FS (top) and a 1st-Generation S&W Model 39-2 (bottom)
When it comes to revolvers, you can find some excellent deals on "previously owned" specimens. All of these, except
the 2.5" stainless Model 66, were bought used for under $475. Most were under $400 (in California, no less!)
Note: The three Model 19's to the right and the stainless Model 66 are .357 Magnums. All others are .38 Special.
The stainless .38 Special serves as my preferred home defense gun.
If simpler is better, there's hardly a revolver that's simpler than the Smith & Wesson Military & Police Model 10.
Rugged, reliable, no frills and nothing to get in the way of projecting lead into away far places.
S&W Model 10 - Old style 5-inch tapered "Pencil" barrel.
The point is, there are a lot of choices out there for good guns in your price range. If a used gun looks good, take along someone who is knowledgeable about firearms to help you evaluate it's condition before committing.