Good and cheap soil and nutrients?

I'm about to start my first outdoor grow but I still need soil and nutrients. I don't have a lot of money to spend on this (trying to keep it under 50 if possible).

I will be using around 5 pots with 1-2 plants in each. What is a good soil for starting in cups then for 3 gal. Pots

I want to get nutrients in powder form so I can just mix it with the water. What's a good kind to get that's inexpensive but affective?

Last question, Is it necessry to use a different soil for the seedling stage in party cups then for the permanent 3 gal. Pots? And how much soil does one bag usually have (in gallons) and how much $$$

first off 2 plants is to many for a pot 2cf of soil will do about 5 3gl pots and peters 20-20-20 is good cheap all around food i satr them in jiffy disks and go straight into the soil im going to use mg soil is good and cheap