Change value in session and save it. Laravel - php

Question

I want to update product price when I submit coupon code I named my coupon as ticket. This is my function:
public function order(Request $request)
{
$products = session('cart');
$ticket_code = Input::get('ticket');
$ticket = Ticket::where('ticket', $ticket_code)->first();
foreach($products as $p){
$price = $p['price'];
}
if(count($products) && $ticket['max'] > $ticket['used']) {
$subtotal = [$price*70/100];
$ticket->used += 1;
$ticket->save();
foreach($products as $p){
$p['price'] = $subtotal;
$p->save();
}
flash()->success('Kuponas sėkmingai panaudotas!');
return view('cart.order')->with(array(
'products' => $products,
'subtotal' => $subtotal,
));
}
else {
$finalTotal = 0;
$subtotal = [];
return view('cart.order')->with(array(
'products' => $products,
'subtotal' => $subtotal,
'finalTotal' => $finalTotal
));
}
}
this code doesnt work:
foreach($products as $p){
$p['price'] = $subtotal;
$p->save();
}
I get error: Call to a member function save() on array
Without the foreach the ticket itselfs works. It changes the price when submited, but only in that one page. Then when I go to payment site, the price is still displayed without ticket used.
THE WORKING SOLUTION
foreach($products as &$item) {
$item['price'] = $item['price']*70;
$item['price'] = $item['price'] / 100;
}
Session::put('cart', $products);

Answer 1

THIS WORKED
foreach($products as &$item) {
$item['price'] = $item['price']*70;
$item['price'] = $item['price'] / 100;
}
Session::put('cart', $products);