i've heard only great things about fox farms soil prices seem about 14-25 dollars. but i just googled it. i might pick some up at a shop near me
Plants get nourishment's from soil and the roots get protected from the harsh rays of the sun, but it depends on what plant you are trying to grow. But In an agricultural technique called hydroponics, there is no soil at all, but the nutrients are provided in liquid form to the root systems.so if you grow your plants using hydroponics way with new growing methods then there is no need to use soil. whereas some nutrients will work as like soil so i think best way to go for it....
Organic is the way to go. You will pay top dollar at dispensaries for organic bud. The cheapest/best soil I would have to say would be the soil you make and develop yourself. Look into composting and the like. The OVERGROW archives have tones of info on this. And what could be cheaper than disposing of yard and food scraps and creating good nutrient rich soil.
The ABSOLUTE cheapest and the VERY BEST organic soil is the stuff I mix myself. I have just mixed 170 gallons of it this year, see my grow journal.
I don't have luck with 'cheap' soils. I've found that the ph is usually acidic, so you have to add lime, then there are bugs sometimes, so you have to buy stuff to get rid of them, also if you look close, you'll find rocks, and sticks, and plastic etc. Not to mention perlite, vermiculite, worm castings or some kind of organic fertilizer. You would be better off starting with good soil in the first place.