you can pick up a nice soil from pretty much any online hydro / gardening store.. fox farm makes a nice product, either ocean forest or light warrior, or both and mix the two, lol... they usually run around 15 /20 bucks for a yard and half sized bag which is good for a few nice sized pots...
there is a link i think it's called something like hydro finder.com and all you do is put in your zip code or city and it will tell you the nearest hydro store.. i've found like 3 stores near me using the site..
i'd try and find a local store instead of online though tbh as the shipping on soil kills you as i just sent some soil online to a friend of mine so that she could start growing again.. i think i paid like a lil over $100 for the two bags of soil i sent her, which would have been more like $30 / $40 if i could have gotten it in a store for her, but she doesn't live in the same state, and i was being generous, lol..