If you are a sole proprietor, you'll report this information on Schedule C: Profit or Loss from Business. Enter the 1099-K as self-employment income and the consignor payouts as business expenses. The expenses will be deducted from the gross income to determine your net income from self-employment.
TurboTax tailors the business expenses to your type of work (i.e., consignment sales) when you enter general information about your business. At the beginning of the Schedule C interview, TurboTax prompts, Tell us the type of self-employment work you do. Enter "Gift Shop" and click Continue. The screen prompts We need a little more info. Choose "Consignment sales", click Continue, and TurboTax pre-selects the expenses most common for this line of work, including commissions you paid, such as consignor payouts. (Click the link to the screenshot below for reference.)
Please see these FAQs for instructions on entering your self-employment income and expenses:
How do I enter a 1099-K in TurboTax Online?
Where do I enter my self-employment business expenses?