Accommodations and travel arrangements

Russian tourist visa invitation can be purchased online here: http://www.ostwest.travel/en/visa/online/
(Please mind that this is not the visa itself but the invitation valid for application for single entry Russian tourist visa)
Plane tickets can be booked online here: www.skyscanner.ru
(Please mind that ordering plane tickets by yourself saves your money on tourist agency fees).
Accommodations: 
Nice small hostel, have one bed rooms as well. Close to metro Ploshad Vosstaniya
M Hotel, corner of Sadovaya and Nevsky
http://mhotelspb.ru/en/
Manifest Hotel, Saperny pereulok
http://manifest-hotel.ru/index.php/en/priceen
Hotel Saint-Petersburg
Hostel 1912. On the Petrogradskaya side (20-30 min walk from the Institute)

Shelfort Hotel, Vassilievsky Island, 25-30 mins walk from the Institute
http://www.shelfort.ru/en/lang-ru-tarify-lang-lang-en-rates-lang

Hotel Talisman in 15 line of Vassiliyevsky Island (that’s quite far but if you don’t mind walking…)
to be booked here::
https://wubook.net/wbkd/wbk/rdbook/
Taiga Hostel. The nearest metro stations are Dostoyevkaya, Vladimirskaya, Zvenigorodskaya and Pushkinskaya.
Also you can you this service to find an accomodation in St.Petersburg, it is very good and simple in use http://www.booking.com/