Php Tally The Total Nasty Bug

[smallc28]

1. Tally The Total Error When I tally the total with an quantity of 2 my php calculate turn short up in php...But when I press the checkout button to paypal everything adds up correctly.....
   
2. Shipment Trouble When I can add 2 or more items to my cart and checkout with paypal my shipment increase to another 10.00 dollars How would I fix that to remain 10.00?
   
3. Tax calculate error the more items I add to my database my shipment changes from 0.08% to 0.02%
   

How Would I fix these errors without any bugs ?

$shipTotal="10.00";

$taxRate ="0.08";

$pricetotal = $price * $each_item['quantity'];

$getTax = $price * $taxRate;

$cartTotal = $pricetotal + $getTax + $shipTotal + $cartTotal ;

setlocale(LC_MONETARY, "en_US");

$pricetotal = money_format("%10.2n", $pricetotal);

// Dynamic Checkout Btn Assembly

$x = $i + 1;

$pp_checkout_btn .= '<input type="hidden" name="item_name_' . $x . '" value="' . $product_name . '">

<input type="hidden" name="amount_' . $x . '" value="' . $price . '">

<input type="hidden" name="quantity_' . $x . '" value="' . $each_item['quantity'] . '">

<input type="hidden" name="shipping_'. $x . '"value="'. $shipTotal .'">

<input type="hidden" name="tax_'. $x . '"value="'. $taxRate * $price .'"> ';

// Create the product array variable

$product_id_array .= "$item_id-".$each_item['quantity'].",";

[Pikachu2000]

Please tell me you aren't using hidden form fields to handle pricing information.

[smallc28]

Please tell me you aren't using hidden form fields to handle pricing information.

Not anymore Using floats

[smallc28]

for the hidden form field that's for paypal

[Pikachu2000]

If that form is presented to the user and then submitted directly to PayPal, you're going to end up giving away a lot of free stuff. It's absolutely trivial for an end user to alter any of those values to anything they want. It will never be in your favor either, I guarantee that.

[smallc28]

then which method would you suggest I use ?

[Pikachu2000]

Ideally, store it in the $_SESSION superglobal array, and write the items/quantities to a database when a customer confirms the order, along with the amounts they actually are being charged. Then send it to paypal directly. I'm not familiar with the specific methods PayPal allows, but to allow the end user to have any access to the manipulate price of something is suicide and can never be allowed.

[smallc28]

yes I've made a session for that in MySQL incase anyone expert programmers try to alter prices / price jacking....You wouldn't happen to know how to create encrypted buttons would you ?

[Pikachu2000]

I'm not completely sure what you're asking . . .