First, these are Soviet (USSR), not Russian (which would mean either pre-revolution or modern era). While we all use country names casually, with philately it's best to be as precise as possible given the number of issuing entities and political overlap.
As for the stamps specifically, the set can have a catalog value of around $2000, but only when they are MNG (mint never hinged). While these appear to be mint/unused, they are likely attached to the album page with hinges, which lowers their value considerably. In their condition, I'd guess catalog value is about $450, so you could realistically expect anywhere from $100-$350 for them all depending on the buyer.
Depends where you are. Few people in the UK - including stamp collectors - would refer to Russia at any period as anything other than Russia. Similarly, collectors would never have referred to Formosa/Taiwan as "China".
The pricing info given by CP is not correct. Check the perforations and you will find that your stamps are the cheapest varieties. They appear to be perf 12 when that is the lowest catalog price and perf 14.5 x 15 when that is the lowest catalog price. Many people are tripped up by these. Look at Scott numbers 276a-290a in addition to 276-291.
Also check for watermark 170 which make the stamps in full or in part Scott 304-323. Also perf 12.
Stamps of the Confederate States of America are found under "USA" in Scott, but that's not really accurate, is it? Scott made an editorial choice, like your example. It doesn't change that the stamps were issued by the USSR, not Russia. Millions of people inaccurately call the USA, "America," but that might cause a few quizzical looks at a BNAPS meeting. Fortunately, not every catalog panders to the lazy convenience of the English-speaking world. Michel at least rightfully acknowledges "Russia and [the] Soviet Union," given that they're different political and stamp-issuing entities. Zagorsky divides into three eras, 1857-1917, 1918-1923, 1923-1991. Even Stampworld separates them.