$100-250, depending on the condition, type barrel, etc.
10-200 USD or so
50-180 USD
The value of ANY firearm is based on the make, model and condition. There are several variants of the Ruger Mk II. Prices could range from $200 to $500.
You will have to call Ruger. You can get the phone number from their web site.
For this particular pistol - Mk I, Mk II, and Mk III - it is highly recommended to let a professional handle this. Many reassembly mishaps have resulted from DIY-ing it with these pistols.Contact Ruger Customer Service at the website, get an owner's manual.
It is a semi auto PISTOL, not a revolver. Value depends on exact model and condition. Roughly $100-$350.
Assuming you mean a Ruger Mk II, it will depend on condition, barrel, sights, etc, but probably $150-$275.
You can request an owner's manual for free on Ruger's web site.
Sturm Ruger still makes magazines for that pistol. They are the same ones used in their MK I variant and have a 9 round capacity. The subsequent variants, the MK II and MK III . They can be purchased on-line at the Sturm Ruger website, and are commonly available at gun shops.
50-290 or so
Generally not sold, so there will not be enough sales to determine a value. A high grade Mk II is around $500
Of course it depends on condition, whether its a MK-I or Mk-II, etc. but the value shows around $300 average.