What is a 1926 15 koneek worth?

The Soviet Union (the abbreviation for which looks like "CCCP") did not produce any 15 kopek (the letter that looks like a lower-case "n" is actually a "p") coins in 1926. They, did, however, produce them out of 50% silver for all other years in the range 1924-1930 - those coins are all worth about US$2 in Fine condition, about US$5 in Extremely Fine, and about US$10 in Uncirculated condition.