Would you do artwork for free?

I was reading in a Facebook group today about someone giving a "contest" for cover art for her to-be-released book. I clicked on the link to read very specific request for the book cover art. It has to be of a specific dimensions and it has to feature a specific object.  

The other requirements is that if you "win" the contest, you give complete right to use the image in any way the writer wants to in related to the book. What does the winner get? The winner gets a link and a credit for the artwork in the book. 

Personally I find it offensive that first it is called a contest. When there is a contest there should be a prize not a link on a blog and a credit for use!  

Second, since there is no mention on the site that the book will be released for free, I think it is offensive that there is no offer for payment of any kind for use of the image. How about $50 by PayPal? That would still be dirt cheap, and at least the artist could go out for a dinner and a movie for all the hard work required to make the kind of cover artwork that was requested.  Do you think several hours to several days of work is worth a book cover credit and a blog link or two? How sad you don't value your artwork.

I want to clarify that I understand that if someone has an EXISTING artwork and wants publicity, I think it could be acceptable.  I do not accept that you should have to make NEW artwork to match very specific requirements just for the possibility that your work will be selected for the cover of a book for a new writer who may not sell anything at all. 

What do you think?  Do you think cool work for free or like me are you upset and a little offended at the whole idea?