Learn English – Difference between to live on and to live by

prepositions

My vocabulary trainer stands "to live on" and my vocabulary trainer says that it means that somebody does something to make one's living (by doing something).

Example: I live on selling cars.

But I have also learned that "to live by" means exactly the same (and I have often heard sentences like "I'm living by selling cars").

Well, my question is: When should I use "to live by" and when "to live on"? Or is one of these prepositions wrong?

Best Answer

From ODO:

live by
supply oneself with the means of subsistence: they live by hunting and fishing

Live by allows the description of the means of subsistence (such as selling cars).

Live on is followed by what you have to live, not what you do.

live off (or on)
• depend on as a source of income or support: if you think you’re going to live off me for the rest of your life, you’re mistaken
• have (a particular amount of money) with which to buy food and other necessities: how much money do you need to live on?
• subsist on (a particular type of food): scavenging seabirds live off discarded fish and fish offal
• (of a person) eat, or seem to eat, only (a particular type of food): she used to live on bacon and tomato sandwiches

So...

I live by selling cars

I live on the money I get from selling cars