One of the other ways to get your food and drink in Russia is from the local street vendors. Vendors range anywhere from people selling ready to go food, all the way to people selling nuts and other such products. People sell anything and everything you can think of and it can be anywhere on the street (not just at the rionok). Some of the sellers have little huts that they are in (often found at the bus stop) while others are right on the street with their stuff. Here are some pictures.
Small shop where fruits are sold.
Grandma selling piroshki (yummy russian food).
Women selling nuts on the street.
Small cakes/pastries seen through the window of a vendor.
A vendor selling russian root beer (kvas). It doesn't taste like root beer. I am not a fan.
Buying anything on the street should be done with care if you are buying prepared food. You never know what they may have put in those piroshki with meat...I've heard some pretty nasty stories about dogs and cats being used in them.