Thank you very much for your response, it was extremely helpful! I have two smaller follow-up questions:
Since there were over 1200 sales made and I don't know the actual cost basis for any of them, while trying to come up with my good-faith estimate, can I take a logical step like "this collection of cards was purchased for $12000 and I sold it for $13000"? Even though some of those items may have sold at a profit and some at a loss, since I have no way of knowing?
Secondly, I received this collection to sell as a gift from a family member at the beginning of the year. Would that affect the proper way to file this?
