Plant Pot Size and soil questions!

I have 4 plants growing and i was wondering what is the smallest possible pot i could use for this plants for there whole life?
What is the best type of soil i could use?

YOu don't need to post a seperate thread for every question you could have. 3gallon pots with soil. VV

sorry about that.

To find gallons, determine the number of cubic inches and multiply by .00372.

wat the best type of soil..and wat chemecials nutrients do i use and at wat part of stage do i start using it.