The Russian rouble is divided into 100 kopecks. There are coins for 5 kopecks, 10 kopeks, 50 kopecks, 1 ruble, 2 rubles, 5 rubles and 10 rubles.
Roubles can be purchased in advance from banks in many western countries and legally brought into Russia. You will probably need some. Most hotels, restaurants and larger shops accept credit cards, but smaller shops and kiosks do not. It is against the law to pay with dollars or euros (although not impossible).
If you arrive without roubles, the easiest way to obtain them is to use one of the many ATMs. There are also exchange bureaus at banks, hotels and terminals. All other exchange bureaus were ordered closed in October 2010. Changing money on the street is illegal.
Prices are not high but are approaching an average European level. Even so, most things in St Petersburg are cheaper than in other Baltic ports.
Everything is priced in roubles. Tipping in restaurants is not obligatory.
Most department stores in the centre are open from 9:00 or 10:00 to about 20:00 hrs (8 p.m.) and some to 22:00 hrs (10 p.m.). Sunday is regarded as a normal working day, although with some exceptions.
Museums have much more conservative working hours than shops, and take more days off. Restaurants are always accessible even into the night, although sometimes hot meals are not available very late.