If you live in the Pacific Northwest it probably only costs about 1/2 that much per bag. Back East it runs about 20 bucks a sack, or more! That's why most all Soils, Fertilizers and Ammendments are made in the "local region" - freight costs are a bitch!
All FoxFarm products come from Arcata, California (Northern California), that's why they cost more the farther East you are.
If you would like to use "FoxFarm Ocean Forest", but the price is prohibitive - TRY THIS:
Buy a 4 lb. bag of "FoxFarm Marine Cuisine" (dry fertilizer) and mix it with a good, premium, local, potting mix. The bag will go a long way (1 Tblspn. for each gallon of potting mix!).