Q. Schedule D is likely more accurate as I considered them as either investment or for a collection rather than regular income.
A. I agree. In the TurboTax interview, be sure to identify the category of investments as "collectibles," which are taxed at a higher maximum rate than ordinary investments.
Q. In this case, is the gain still calculated as the net spent vs net sold of all the cards combined?
A. Yes, collectible losses can be netted against other collectible gains during the same year. But, losses by collectors from sales cannot offset other categories of capital gains (if you have a net loss, you do not get a deduction).
References:
https://stamps.org/news/c/collecting-insights/cat/ap-bonus-content/post/tax-strategies-for-owners-of...
https://www.thetaxadviser.com/issues/2019/nov/taxation-collectibles.html
Q. Do I factor in shipping costs?
A. Yes. Enter as expenses of sale.
