Tipping

Tipping is a very new concept in Russia, but it is slowly becoming (kind of) expected. It’s not at all like in many other Western countries, though. Unless you’re at an extremely expensive restaurant, a 10% tip is appropriate and anything higher is nice but not expected. It is usually not necessary to tip during a "business lunch".

http://gorussia.about.com/od/practical_information_russia/a/How-To-Behave-In-Russia.htm