International shops once called "hard currency shops" (valyutnyy magazin) which sold goods (usually imported or Russian souvenirs) for hard currency only have been legislated out of business by new currency laws. Virtually all legal transactions should be carried out in rubles (even if prices are stated in dollars or DM). The basic exception to this rule is in payment by credit card and to airlines.
Thus, when you see dollars/rubles ($/rbls), it usually refers to shops or firms that set their prices in dollars, etc. but only accept payment in rubles at the current rate of exchange.