Prices listed here is not altered by harvest sprite discount or reduce material powers. Prices differ from IOH prices, but material is the same. Please note: Use Gannon's Lumber is the price listed in-game after the Lumber and Cost, marked as + Materials. It is the total cost if you were to choose that option from Gannon. It is more costly choosing Use My Lumber option than buying the lumber for 50G a piece directly from Gannon for some odd reason.