From the Nemesis vcoins.com store:
http://www.vcoins.com/ancient/nemesis/store/dynamicIndex.asp
  
 Gordian III Æ 26mm of Odessos, Serapis 

 OBVERSE: laureate, draped & cuirassed bust right 

 REVERSE: Serapis standing left, holding patera & cornucopia, 
 altar at feet. 

       25mm - 11.2 grams       Price 
         US$ 39.99  € 32.74
        £ 22.21
        AUD$ 52.93
        CHF 50.87
        CAD$ 47.92

       Rates for 8/24/2005