We took the 10 day River Trip in Russia. We were told that taxis would overcharge us and not adhere to previously agreed fees.
We had no trouble getting a taxi to the dock in St. Petersburg for about $38 for 2, Gate 1 price, $181 for 2. We did not see online how easy or difficult it might be at the Moscow dock so took Gate 1 transfer for $181. They called a taxi for us and he handed us a receipt for 1200 rubles or about $38.
They made a $143 profit!
They are the Motel 6 version of river tours, tiny cabins, limited service, drinks provided only at meal time, lousy wi-fi service.
We had some good local guides, but not all. Think carefully before signing on.