There's an alternate way to do it. You use the inventory section (line 36, section III of schedule C) to enter your purchases of goods to be sold.
In TurboTax (TT), when asked about inventory, check the box "My business buys and immediately resells goods". Next select "Cost" for your method of valuing inventory. When asked for your beginning and ending inventory, leave both boxes blank. On the next screen you will be asked to enter your purchases (and, in separate boxes, any other costs you want to assign to cost of goods sold).
