i paid 20$ for 1.5 cubic feet of Ocean Forest. You may want to use Light Warrior or something without fertilizer though, as your plants are still so small--Ocean Forest can be a bit hot for small plants. Check Fox Farm's website, they have a list of stores in your area that carry their stuff. I've only ever been able to find it at hydro stores, but maybe organic gardening stores would carry it? (i dont actually know, just wondering...)

Good luck!
DrSpiggity