Expect to pay about 10% on tips in restaurants.
Be aware that you will pay more to attend a museum or that tickets to a ballet or a play will cost you more than they will cost a Russian. This is accepted practice.
Taxis: In Moscow and Saint Petersburg there are many “gypsy” cabs. There are not enough marked taxis at present. Many taxi drivers use an ordinary looking car. Also, some people who do not regard themselves as taxi drivers will occasionally pick up a fare if going in the right direction. Be warned that you may pay several times too much if you are obviously a foreigner and do not know the true rate or how to negotiate in Russian. The rates are also higher if the taxi is caught near a popular site or at a busy time of day. For instance if you catch a taxi in front of the Hotel National in Moscow, you will typically pay much more than if you walk under Tverskaya to the other side of the street-perhaps 2 or 3 times as much. A Muscovite would expect to pay no more than about 500 rubles to travel from the center to virtually anyplace in Moscow. If you are paying this much or more to travel a short distance in the city center, you are being taken advantage of.
You should not take a great deal of foreign currency with you as there are restrictions on what can be taken out of Russia (currently $1,500). There is no limit on how much you take into Russia, but it must be declared. Of course, it is always risky to carry large amounts of cash anywhere. There are many places in Moscow and Saint Petersburg to exchange money, but you may not always get a fair exchange rate. The best alternative is probably to use an ATM card as the machines are now ubiquitous in most sizable cities. However, there have been reports of scams involving some where individuals PINs were stolen and accounts accessed. It would be best to use one inside of a bank and to examine your accounts carefully upon your return. In Moscow and Saint Petersburg, American Express will not be accepted by most places of business and it is almost impossible to use the card anywhere else.
Be aware that many hotels in Russia will attempt to charge you a higher rate if you are obviously a foreigner. Also, even the best hotels in Moscow and Saint Petersburg will follow this practice: You will be quoted a rate in dollars, but they must accept all credit card payments in rubles. They will often give an unfair exchange from dollars into rubles, so that your bill can be 5 -15% higher than you expect. It would be good to negotiate this with the hotel before your arrival so that you do not have any nasty surprises. If you plan on staying any length of time in an expensive hotel in Moscow, there is an alternative: you come to an agreement with the hotel on the price and wire them the money in dollars ahead of your trip.
In the centers of Moscow and Saint Petersburg hotels, restaurants and other services can be quite expensive. Outside of these areas, prices may seem very modest. There is a huge disparity, but of course there are differences in quality, amenities and location.