How much is a Lars Hansen autographed reprint worth?

A student is trying to find out.  He emails me:

I'm a 1st year MBA student at Chicago Booth -- where even the Marketing Professors have a PhD in Economics. 

I'm taking a class this quarter called Entrepreneurial Selling (more info here). One of the coolest assignments is a bartering challenge: Prof. Wortmann gives everybody a simple Chicago Booth pen and we need to barter it for something with larger monetary value, and then keep bartering once a week until the end of the quarter. 

I did my first trade with Prof. Lars Peter Hansen (Economics Nobel Prize 2013). In exchange for my pen, he gave me an autographed copy (he wrote a cool anecdote as well) of his most famous article. I'm now running an auction at eBay (it's OK to trade things for cash): see here.