I found a list of acquisition costs for various munitions.  30mm HEI rounds, $24.75 a pop.  A one second burst of that will set you back ~$1600.  Oddly enough, the API rounds aren't on the list.  Priceless perhaps? :lol:   
You could have 65 Mk-82s for the price of one AGM-65D.   
http://www.fas.org/man/dod-101/usaf/docs/munition-cost-11-1.htm