Here's one
https://www.youtube.com/watch?v=t8LtQhIQ2AE
Note that this is during the fall of the soviet union, so the stores are probably emptier than usual (they would usially not be full either). For a lot of things you would need stamps to buy (in addition to money, these things were rationed).
This might be closer to the village stores.
https://www.youtube.com/watch?v=rfxCa2WWsJM
A few others
https://www.youtube.com/watch?v=lAvV6z2FG24
https://www.youtube.com/watch?v=cFA0TSWPQ-U
https://www.youtube.com/watch?v=ZKVhrzhAI8I
The average store would be like a mix between a warehouse (often an empty one) and what a convenience store should be like. Most everything is rationed and/or expensive, there's no real choice, you get what you get and the quality is often times questionable. This is mostly because from the start to finish, everyone that's a part of the supply line would take their piece of the pie first, not to mention the privileged classes that would get the most premium products - be it food or whatever else. Then the factory workers would take some, the truck drivers, the border guard, the store employees and thus the common man would get whatever is left, if that. Pretty much the only concrete way to get any kind of premium product was to offer services or goods for services or goods. You could have all the money, but without ration stamps or permits you couldn't do anything with that, thus the bartering.
Stuff that would be available would be any kind of grain products, vegetables, and meat and dairy in smaller amounts and depending on the location. Pretty much everything else you could consider a premium product.