by SuPeRGriM
To further add clarification, the sawmill can not be bought for zero francs. It can be purchased for 14 francs (the cost of most, if not all, of the buildings/boats are also the Victory Points you will receive at the end). You CAN, however, enter or use the building for free.As @seepieceeggshell has mentioned, buying is free. So, you can buy a building (as the free action) and enter (use) the building on the same turn.