$items = $_REQUEST['items'];
$newitem = $_REQUEST['newitem'];
if($newitem != "") $items[] = $newitem;
?><pre><?php
echo "request<br>";
print_r($_REQUEST['items']);
echo "newitem<br>";
print_r($_REQUEST['newitem']);
echo "items<br>";
print_r($items);
echo "session<br>";
print_r($_SESSION['items']);
?></pre><?php

$name = $item['name'];
$quantity = $item['quantity'];
$price = $item['price'];
echo "vars: ", $name, $quantity, $price;
The result:
request
newitem
Array
(
    [\'price\'] => 36.00
    [\'quantity\'] => 1
    [\'name\'] => Old Fashioned
)
items
Array
(
    [0] => Array
        (
            [\'price\'] => 36.00
            [\'quantity\'] => 1
            [\'name\'] => Old Fashioned
        )

)
session
Array
(
    [0] => Array
        (
            [\'price\'] => 36.00
            [\'quantity\'] => 1
            [\'name\'] => Old Fashioned
        )

)

Array ( [\'price\'] => 36.00 [\'quantity\'] => 1 [\'name\'] => Old Fashioned ) vars: