This word, халява, it is interesting. Google translate translates it as "freebie", but Russian students use it to describe a situation when they didn't study for a test and get an "A" anyway. "Freebie" doesn't really apply here. Google image search turns up a lot of interesting pictures for халява. But finding an English equivalent is proving taxing. I'm thinking of:
"blind idiot luck" * gravy train * sependipity *
but I don't think any of those are exact translations.
что-либо, полученное бесплатно, задаром, "на халяву"
, and if this is correct, then it applies perfectly to the situation with students, that you described.халява
means 'a prostitute'