Talking to Wulbren in the prison, choose yes I found something (a hammer to give him).

Up pops a trade dialog of me and him. I drag the hammer over and it says he has insufficient gold for the transaction.

WTF. The hammer is free. It's a jailbreak!

I tried several things, including Wulbren's hammer itself. What am I doing wrong?

Yes I know I can throw it to him. Thought I'd try something different.