At the Barter Shop, you can barter items in your Inventory for items offered in the Barter Shop. Not all items that are available on the market are available here, only some items are. The barter you make must be of equal gold value, as determined by prices set in the barter shop. For example, in the image shows, the price for a Depraved Seed is set at 10,000,000. The price for Sea Elements in my inventory are set at 100,000. So, I can barter 100 Se Elements from my inventory to obtain 1 Depraved Seed.