How much are you "into it"? Should it matter....

[Frankish]

From an economic perspective, the sunk cost, as it were, is irrelevant (tax advantages/implications aside). But it's a hard logical fallacy to get around. I know I always feel bad letting something go for a lot less than I paid for it and feel like a genius if I sell something for multiples of what I paid for it...mostly in other fields, as I haven't really sold cards. But it really shouldn't matter at all....

[RayBShotz]

This may sound a bit odd.
If I've held a card for a while, I no longer equate it to what I paid. In a lot of cases I don't even keep a record.
Everything I make if I ever sell it is 100% profit to me at that time of sale.
I usually look to get market price at that time but most of all just want to make a good deal for both parties.
To the Great Exhibitman's point; sometimes a trade or a trade and cash makes things even more pleasant.
RayB