You can get a wonderful firearm for less than $600. Will it say "Sig" on it? Maybe. You can get a 2022 for $400. Sure you get what you pay for. Sometimes that thing you are paying for is naught but a name and a feeling of misplaced superiority.
Ruger is always a good choice.
The CZ guns are great, and their clones (EAA witness) are often seen under 280 dollars.
(unfortunately, this ad is for a 40 S&W, and my slickguns websight is out of orderhttp://grabagun.com/eaa-tanfoglio-poly-40-s-w-12rd.html
Here ya go, the websight is working now:http://www.slickguns.com/product/eaa-tanfoglio-witness-ps-9mm-45-barrel-16-rnds-30319http://grabagun.com/eaa-tanfoglio-poly-9mm-16rd.htmlhttp://www.budsgunshop.com/catalog/product_info.php/cPath/231/products_id/411548803
The Witness line is solid. My favorite gun right now is my Elite Match 10mm, and I've had a few others in the past. Great firearms!