I have a number of high value textbooks. Amazon is pricing them around $100 each. Its Deductible only allows $20 each. How do I claim fair market value?

[Texas Roger · Accepted solution]

If you can justify to the IRS a higher value than the value assigned by Its Deductible, you can enter a Custom Value for whatever price you believe is the fair market value. 

[SweetieJean]

If OP is donating them to, say, Goodwill, I suspect they will sell there for a lot less.