Apparently you can sell your 2014 Boston Marathon Medal for close to $400
http://www.ebay.com/itm/Boston-Marathon-2014-Finisher-Medal-/161282538270
I heard that last year's are going for upwards of $600.
I don't plan to sell mine, but those figures are intriguing. Good way to make up for the entry cost if you're strapped for cash.