Remove any magazine and ammunition. Loosen the barrel band by loosening its screw and pull the band off. Unscrew the screw under the stock that holds the stock to the barreled receiver. Move the safety to the middle position, then separate the barreled receiver from the stock. Unscrew the 2 hex head bolts that hold the barrel onto the receiver. Pull the barrel out of the receiver. It should go back together in the reverse order that it came apart.
Depends on what caused the jam.
Check the receiver and barrel
100-300 or so
Yes, Ruger made them
50-200
Ruger.
Ruger's web site has extensive sn data.
75-300
50-225 usd
Not recommended.
50-200
it is worth ..............$$$$