Form 1099-K reports amounts that you received, not amounts that you paid.
If the purchases that you paid for with PayPal are personal expenses, you don't report them on your tax return at all. If they were business expenses, you enter them as business expenses and they will go on Schedule C. But the tag below your question indicates that you are using TurboTax Deluxe Online. You cannot enter business expenses in TurboTax Deluxe Online. You would have to upgrade to Self-Employed, or use any version of the CD/Download TurboTax software.
If you receive a Form 1099-K for money that was paid to you, you report it in the appropriate place on your tax return, depending on what the payments were for.
In a question that you posted a few days ago you indicated some uncertainty about whether your purchases and sales constitute a business or are personal. It might be a good idea to consult a local tax professional to clarify the nature of your buying and selling, and how you have to report it. If you want to try to get clarification here, you have to provide a lot more detail about exactly what you bought and sold, and for what purpose.
If you want to continue this discussion, please continue in this thread. Do not post any more separate questions about your buying and selling activity. When information is scattered in multiple threads it's confusing and hard to follow, and hard to see the whole picture.
