100-400 USD
Although they have been discontinued and a little hard to find they are selling at gunshows, September 2009, for from $400-$500.
Ruger's web site has sn data.
100-1000 depending on specifics
No such model in the Ruger line.
You can download the manual for the Old Army cap & ball revolver that has loading and cleaning instructions from the Ruger website (see related links) under the customer service heading.
Ruger's website has serial number data on its products.
Go to the Ruger website. There is a section to date your 22 by serial number.
Do a search on the "Ruger Old Army User Manual". It is a free download and will answer all your questions.
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.
If Ruger's website is up, they have extensive sn data on it.
Ruger has a sn search function on their web site.
Go to Ruger's website. They have a sn look up section.