Concert Ticket Sales reported on 1099-K

I have read various other posts on this subject but still not sure how to handle this.  Received a 1099-K form from Ticket Master showing, in box 1a, a $1,900 Gross Payment to me for ticket sales.  My cost for the tickets was $1,600 so my net profit for the sales was only $300.    This is not a business and not a hobby.    I just bought too many tickets so I had to sell a few. 

Right now, I'm being taxed on the full $1,900.   

Where do I make the adjustments to show my cost was $1,600 resulting in a net profit of only $300. 

(I do not itemize deductions.)   

Thanks