ArrayMultiSort.php

<?php

$arr = [
    'car1' => [
        'price' => 40,
        'title' => 'car 3',
        'brand' => 'VW'
    ],
    'car2' => [
        'price' => 30,
        'title' => 'car 2',
        'brand' => 'VW'
    ],
    'car3' => [
        'price' => 50,
        'title' => 'car 1',
        'brand' => 'VW'
    ]
];

$priceArr = array_column($arr, 'price');

array_multisort($priceArr, SORT_ASC, $arr);

echo '<pre>';
print_r($arr);