Here's how I'd report a 1099-K for the sale of collectible items:
1. Go to "Income from Form 1099-K" in the Personal Income section.
2. Choose "Personal Item Sales" as the Income Type.
3. Enter the info from your 1099-K.
4. If you want to report your cost basis as zero, do not check either box on the "Personal Item Sales" page.
5. Click "Done" on the "Your 1099-K Summary" page.
6. Then go to the Investment Income section.
7. Click on "Stocks, Mutual Funds,..." button.
8. On the next page you should see a line with your 1099-K payor's name. Click the "Edit" button.
9. On the "here's all the sales reported..." page, click "Add".
10. Click on "I'll enter one sale at a time". (Clicking "summary" doesn't seem to work for this purpose.)
11. Enter the data for one of your collectible sales. Write "Collectibles" for the description (without the quotes).
12. On the next page, "Any of these less common items...", check the "Proceeds from Collectibles" box.
13. Repeat the process until you've accounted for all your sales. Be sure your total sales match the 1099-K reported amount.
This process should result in your sales being properly reported as Collectible sales on Schedule D and Form 8949 of your tax return.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
