I need to know where I can find this in Scott. I know it's Russia AR3 (Year = 1918), but I just can't find the right volume and page. Thanks for any help!
My understanding is that it's a savings stamp used as postage. I found a few references online to AR3. I was searching through some other references in Scott and I understand that to be a postal-fiscal code designation in Scott (like AR1, AR2, AR3, AR4, etc.).
The Russian postal-fiscals were not added to the standard Scott WW catalogs until the 2010 Scott catalog. It appears between the regular and semi-postal sections of the Russia listings.
In the 2014 Scott, your stamp is Russia #AR3(12Jan1918) at 35¢ for an unused single.
Not sure if it might have appeared in the Scott Classic Specialized before 2010. My most recent Scott classic is 2007, and it's not listed in there.