I have seen very few used SR9 Rugers at my local gun shops. However you can buy a brand new one for around $360.00. That is a pretty good deal if they get some of the bugs worked out.
The Ruger SR9 uses a proprietary magazine.
I paid $439 for mine at Outdoor World. MSRP is 525
It doesn't.
Try e-gunparts.com or Mec Gar
No, they do not use the same magazines.
Can't be answered without a DETAILED description of ALL markings, to include label on box.
125 USD
It all depends on the model, caliber and condition of the Ruger. If I asked what is the price of a used Chevy you would probably ask. Which one, how old, what condition, Which engine. How many miles? It's the same with a used Ruger.
Go to gunbroker.com look what they are going for...
200-400 USD
100-200
75-125 or so