addParam.php

<?php
$api = new DatafeedrApi(MY_ACCESS_ID, MY_SECRET_KEY, 'curl');

$search = $api->amazonSearchRequest(MY_AMAZON_ACCESS_KEY, MY_AMAZON_SECRET_KEY, MY_AMAZON_ASSOCIATE_TAG, "US");

$search->addParam('Brand', 'nike');
$search->addParam('Keywords', 'shoe golf');
$search->addParam('MaximumPrice', '1500');
$search->addParam('SearchIndex', 'Apparel');

$products = $search->execute();

foreach($products as $product) {
	print_r($product);
}