I have mostly a baseball card collection with over 1000 cards that were gifted to me I want to sell. How do I determine cost basis? Can I enter $0 since I don't know?

[xmasbaby0]

We answer income tax questions here in the user forum.  We cannot advise you as to the value of a baseball card collection.

[jsbchevy17]

That's not really what turbotax stated when I entered my question in. Besides I did not ask for the value of my baseball card collection. I have a pretty good idea of what it's worth. I asked a tax question on how I personally can determine the cost basis for my collection when it was gifted to me since I need to know that compared to what I sell it for. If I can just claim $0 as a cost basis, even though that would raise the tax burden, that would be useful information to me...