I think I would keep the card I have if I might not end up with money to spend once it's all settled.
I mostly do low end stuff, so low we just include any hobby money I get as misc income(the gross, like if I sell a card for $10 i report $10. Yes, we pay extra in taxes, but in most years it's not even enough to worry about. And figuring out a reasonable cost for things bought in large lots 40 years ago seems crazy. Like is my Gretzky rookie the $50 the entire 5000 count box of hockey cards cost? Or is it .01 ...........
Of course this has brought up many questions for me, since I've collected for decades. I essentially have no records pre-Ebay. And after Ebay only have a messy archive of "you won!" emails.
And how does cost basis work trading the other way. Like I buy a lot of stamps on Ebay, $40 for six. They have a wide range of catalog values, all have varieties making them more valuable than the basic ones they were described as. Some aren't cataloged and are hard to place an accurate value on. One is around $2000 catalog value. Two years later I swap that stamp plus cash for a different stamp that has a slightly higher catalog value. (
literally the only way I could have ever gotten one) How the _ do I figure that one someday when it gets sold. Or more likely how do my kids figure the value.