I'll be visiting St. Petersburg for two days this summer, and I'm in the midst of collecting some Rubles ahead of time. Question is, I have no idea how much to bring.

Current exchange rate is: $1 = 67.11 Ruble

I'm assuming most places in St. Petersburg won't take credit cards very easily, but with that high of an exchange rate, I don't want to carry a trove of cash either. So, say I had $200 worth in Rubles: How far would that get me around there? (i.e. - coffee shop, lunch stop, tickets to a museum, a subway ticket, etc)