For the most part, you'll be shopping in Moscow and St. Petersburg in stores which operate the same way they do in the US. However, there may be times when you'll stop in at a Russian store which still uses an older, and at times frustrating, multi-step system of purchasing and payment:
Decide what it is you wish to purchase. Ask the price.
The salesperson will give you а чек and ask you to pay at the касса. While you are doing that, he/she will be wrapping up your purchase.
After paying, you will return to the salesperson with either a receipt showing payment, or your original чек stamped, which you'll hand over in exchange for your purchase.
Russian law now stipulates that there is one currency for the entire country and that is the рубль which is divided into 100 копейка. Because of inflation however, копейки have disappeared. In spite of this law, you will still be able to make purchases in many stores (especially those which are foreign-owned) using СКВ свободно конвертируемая валюта freely convertible currency (dollars, marks, francs and pounds sterling). Major credit cards are readily accepted in many locations in Moscow and St. Petersburg, more rarely in other large cities, and almost never in the smaller ones.
Think big when you think of prices in Russia! When writing these large numbers, Russians use а точка period to indicate the decimal point rather than а запятая comma.
For example:
12.000 руб.= 12,000 rubles
7,5 руб. = 7.50 rubles (7 rubles and 50 kopecs)