How should a democratic, constitutional country eradicate vote-buying?

I wonder if some developed countries ever had the case of vote-buying in the past, say, some 100 years ago or more, and how they managed to control it as well as how people were and are aware of their rights for the sake of national survival, development and prosperity, cash or other valuable means or things as such should be dealt with business alone. Any experience/knowledge from history? Thanks.