nutrient help ebb flow

hi im a newb to growing and i am in the process of germinating my seeds. i have my ebb and flow set up but im waiting to buy nutrients because im not that well informed on them yet. i saw a few 3 part kits but still kinda expensive. i was wondering if there are any cheaper alternatives?

three part sytems are the cheapest way to go like GH Micro,Grow and blow on advance nutrients.