Ruger has sn data on their website.
100-400 or so
They were made in several calibers- will be marked on the barrel.
i see them on auction for around $500 all the time
100-1000 USD or more depending on specifics
75-1000 USD depending on EXACTLY what you have.
50-350 USD or so
Ruger's web site has sn data.
For sale ads, gunshops, gunshows, e-gunparts.com
100-1000 depending on exactly what you have, condition, box, accessories, papers, etc..
Call Ruger and they will tell you. SN info is also on their web site if you can access it.
The Blackhawk was not made in 22 LR. If you have one with "Blackhawk" on the frame, you need to call Ruger. There is an almost astronomical chance that you could have a factory experimental, but, I doubt it. More likely you have a Single Six of some type or maybe a Bear Cat. Any of the 22 revolvers can range from 50-400 depending on specifics.