I need help choosing a car..............?

I have my own landscaping business so that means I am always on the road in my truck I have a 1994 toyota pick up truck extended cab v6 engine. I spend a thousand dollars on gas monthly. I need to get a truck with a v4 engine because I was told it waste less gas. Is this true and how much would I save compared to a v6? Is there any way I can trade it ?