Go to gunbroker.com look what they are going for...
Depends. I got mine used for 450$ some of the NIB (new in box) i've seen go for as much as 850$
Go to Ruger's web site
They can go anywhere from $500 to $1000, depending on a number of different things. Ruger made a few different models of the Mini-14, and changes to models over the course of its production life (which started in 1973).
Call Ruger and they will tell you. Go the Ruger website and use the serial number date function.
Go to Ruger's website and request a owner's manual
New, a basic model runs between about $250 and about #325 depending on where you buy it. Used, they usually go for about $200 in good condition.
Ruger will send you a manual for free if you go to their website. Alternatively, go to a gunsmith and ask for help.
Go to Ruger's web site and request a manual.
Ruger has extensive sn data on their website. You will have to go there and look it up.
Anywhere from $100-275, depending on condition, barrel, sights.
Go to Ruger's web site to find out.