Queens Gambit accepted.

I am surprised to find after playing 20 games here on chess.com that 3 of my won games were from players in the 1300 to 1500 ratings, that fell for the saving of their c pawn at all cost and yet couldn't survive from their mistakes. Is this a common opening error on blacks part? And is there any other way to save the c pawn without loosing time or a piece?