$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.
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.
You will have to call Ruger. You can get the phone number from their web site.
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
If it's a .22 Ruger semi auto pistol, it's probably a Mk. I, Mk. II, or Mk. III. See related link 'Sturm, Ruger & Company'. On the left side of that website, there'll be a menu of their products, including their rimfire pistols. Click on 'Rimfire Pistols', and you'll see a drop down menu which will have their rimfire pistols, including the Charger and Mk. III. The Mk. I and Mk. II are simply older versions of what the current Mk. III is.