The numbers 10-21133 are the serial number that was assigned to your Ruger Standard Mark I pistol,which was made in the year 1969.
Ruger website, customer service, historical data- and you need the MODEL of the pistol. Your serial number indicates that your Ruger pistol was made in the year 1976.The ending serial number for that year was 13-48646.
Ruger has extensive sn data on their website.
by serial number
Ruger has a sn function on their web site.
50-200 USD or so
You can request a owner's manual at the Ruger website.
20-200 USD or so
50-160
Go to gunbroker.com and look under Ruger.. It will give you a ball park...
A call to Ruger will get you the answer.
Upload a photo of it to a gun forum to identify it, guns are not identified by their serial number, they are identified by their model name. For example : Ruger Charger, Ruger Mark, etc.
$100-$250, depending on condition