Helena is right, Moscow salaries are not to be compared with rural salaries.
Even at that though, $70/month is too low. Starting salaries in provincial areas are about $200 for basic work. The worst off are actually those working in academic fields, such as teachers and doctors, they do start at about $100-150. They possess skills that the nation needs, but which capitalism doesnt value. Unfortunately, oil-rich Russia cares less about its own country's good than owning the newest 7 series BMW or Porsche Cayenne. I find it entertaining to see the newest Mercedes M-Klasse Jeep as a police car in Moscow... for a district police chief of course.
Rural girl's are desperate for cash, this is true. But really, $70 will get you nowhere in Moscow and doesnt get you far in rural Russia either... at least if you want to live like a modern girl... and believe me, Russian girls are obsessed with looking good and enjoying life and that costs $$$. This also explains why Moscow and larger cities continue to grow and Siberia and rural Russia is bled out.
As for Moscow prices, its a mixed bag. You can still get laid, even an overnighter, for $100 if you are lucky. But it is the exception and not the rule. "Entry level overnighter" for a girl in the 6-8 category costs $150-250. Quite frankly, I think $100 is a fair price for 2 hours of mid-level sex in Moscow, provided the service is good. You can get laid for $70/hour as well, provided 1 hour is enough. It really isnt for me... I need at least 2-3 hours otherwise I feel I've just wasted my money.