100-550 or so
50-500 usd
100-425 or so
Assuming that it is in excellent condition in the range of $400 to $450.
50-200 or so
Contact Ruger
Probably about $300 - $400
You will have to contact Ruger
400 or so
100-200
100-500
You could either take it to a gunsmith or put it on yourself. I had a Ruger 10/22 and I think it had a scope rail for mounting. Should be just a matter of tightening it onto the rail and sighting it in.
Mine has a nice clear Simmons.