public class PrimaryQuoteObj {

       public String quoteId;
       public String baseModelName;
       public List<String> accessorySKUs;
       public Double baseModelCost;
       public String skuNumber;
}

global class ExtCalloutController {

   WebService static void getPrimaryQuoteDetails(String id) {
          HttpRequest req = new HttpRequest(); 
        //Set HTTPRequest Method
          req.setMethod('GET');
   
        //Set HTTPRequest header properties
          req.setHeader('Connection','keep-alive');
          req.setEndpoint('http://cxyz.row.com/myApp/getPrimaryDetails.htm?qId='+id);
          Http http = new Http();
          try {
               //Execute web service call here     
                HTTPResponse res = http.send(req);  
                System.debug('Response Body = ' + res.getbody());
                PrimaryQuoteObj priQuotedetails =(PrimaryQuoteObj)System.JSON.deserialize(res.getbody(), PrimaryQuoteObj.class);
                //Helpful debug messages
                System.debug(res.toString());
                System.debug('STATUS:'+res.getStatus());
                System.debug('STATUS_CODE:'+res.getStatusCode());

        } catch(System.CalloutException e) {
            //Exception handling goes here....
        }  
       // return null;   
    }
}