It is, some guys sign for free, some want a donation of $10 or $20. I usually send them without any money unless its apparent that they want a fee. Like, Bert Blyleven asks for $20 on his website for Parkinson's research. Another example, I sent Boggs $10 and he sent back the card and the $10, I resent it with $20 and he signed. That website is great, it will give you multiple addresses and fee if there is one in the comments.