This type of Russian visa is for those who have relatives or friends in Russia able to get a Private Invitation.
It is valid for one entry only.
Visa Invitation: Private Invitation issued by the local department of the Federal Migration Service (FMS, formerly PVS) of the Russian Internal Ministry by the request of an individual.
Though the price is not high, the procedure may take up to three months.
Depends on the Consulate. Usually the Consular fee is minimal, but the procedure takes more time than for a Business visa.