亚马逊为aws广告api返回零价格

Question

i am using aws advertising web services to sell product of amazon but i am not getting price for all products of shoes category. I don't know where i am wrong

http://webservices.amazon.in/onca/xml?

array(  'Service'       =>  'AWSECommerceService',
                                'Operation'     =>  'ItemSearch',
                                'AWSAccessKeyId'=>  '************',
                                'AssociateTag'  =>  '*****',
                                'Version'       =>  '2011-08-01',                               
                                'SearchIndex'   =>  $searchIndex,
                                'BrowseNode'    =>  "Shoes",
                                'Condition'     =>  "All",
                                'Keywords'      =>  $searchKeyword,
                                'ItemPage'      =>  1,
                                'Availability'  =>  'Available',
                                'ResponseGroup' =>  "SearchBins, Images,ItemAttributes, Reviews, EditorialReview, OfferListings, OfferSummary, Offers",
                                'MerchantId' => 'All',

                                'Timestamp'     =>  $timeStam//'2014-08-03T09:14:10.000Z'
                            );