How to go by the subway for 26 rubles?

Today trip cost in the subway Moscow on the three card makes 38 rubles. In case of purchases the ticket for one trip in cash desk, cost will appear 55 rubles. But now everyone in a wallet has at least one, and even some plastic cards of different banks and Payment system, or virtual cards are issued and any Payment system in smartphone are used. Some of them allow a decent discount for journey...