If you’re using public transportation in Moscow, the Troika Card is the most cost-effective option. They cost 50 rubles, and save you money on rapid transit. Now there are several new ways to top up your card without going underground and digging around for cash. If you’re a tourist you can return the plastic card for a refund- and it’s cheaper than the London Tube.
Troikas can now be topped up using Rosbank ATMs and online services. The service is available in the payments section of the ATMs and only requires the number of your transit card. The card can also be topped up through QIWI payment terminals, Yandex money, BTB 24, Bank of Moscow, Alfa Click, and by texting the number 3116.
More information is available at the Troika website: http://troika.mos.ru/en/about/
Pro tip: Troika can be also be used for city bicycle rentals and Aeroexpress tickets.