Using PHP internals (no frameworks). Please create a new array with only the entries from July.

test.php

<?php 

    $data = [
            (object) [
            'name' => 'Ring [A0123]',
            'price' => 25,
            'created_at' => '2016-07-20',
        ],
            (object) [
            'name' => 'Pendant [A0124]',
            'price' => 55,
            'created_at' => '2016-07-17',
        ],
            (object) [
            'name' => 'Earrings [A0125]',
            'price' => 15,
            'created_at' => '2016-06-20',
        ],
            (object) [
            'name' => 'Bracelet [ABCDE]',
            'price' => 15,
            'created_at' => '2016-06-23',
        ]
    ];

    var_dump(array_filter($data, function($product){
        return date("m", strtotime($product->created_at)) === "07";
    }));

//Hi everyone, you can comment it. =)