Tickets are paid... 400RUR or 11EUR. Booking is not easy, it has to go to one of these sites:
http://www.concert.ru" onclick="window.open(this.href);return false; - http://www.concert.ru/Actions.aspx?book ... 4&CityID=0" onclick="window.open(this.href);return false; to buy by a credit card for example
http://www.biletmarket.ru" onclick="window.open(this.href);return false;
http://www.mta.ru" onclick="window.open(this.href);return false;
http://www.kontramarka.ru" onclick="window.open(this.href);return false;
http://www.parter.ru" onclick="window.open(this.href);return false;
http://www.ticketland.ru" onclick="window.open(this.href);return false;
http://www.artmetro.ru" onclick="window.open(this.href);return false;
http://www.19-00.ru" onclick="window.open(this.href);return false;
http://www.kassir.ru" onclick="window.open(this.href);return false;
But I suppose it will be possible to buy a ticket at one of many box-offices in center of Moscow.
These links can be useful(only RU)
http://www.bizav.ru/visit/" onclick="window.open(this.href);return false;
http://www.bizav.ru/place/" onclick="window.open(this.href);return false;
http://www.bizav.ru/contact/" onclick="window.open(this.href);return false;