1099-K form change $20,000 and question about reporting taxes with SmugMug

I have a question that may be hard to answer. I sell photo prints on a platform called SmugMug. The company has set prices for all its print sizes through a third-party photo lab. I upload my photos, and then raise the price by 60%, and I collect that 60% plus the base price when each print sell. Example: Base cost for print $40, I increase the price to $64, I sell the print, the company charges the customer for shipping and ships the print through BayPhotos, the print lab, to the person, and I receive $24. After my sales reach $500, they send the money to my bank account. The main part where I am confused is that I only receive money from Smugmug for the amount I raise the base print price. I am not receiving money in my bank account for shipping or the base cost of the print. I am also printing or shipping it; that's the company's responsibility. So what amount will I report when I reach the schedule C area. Thank you