Shipping Avalible Based on Order Amount?

Hello,
I am trying to set up a offer so when someone buys more than 3 boxes of the product they can then choose Fast Shipping. But I want them to only get that offer if they order more than 3 boxes, lower is just basic shipping. Any help is much appreciated.

Thank you.

That would require a custom module, but it's certainly possible

Hi,

All the shipping modules are on the following folder
/includes/modules/shipping/

Each file is a shipping module and contains a PHP class
Every class has a function/method with the same name as the class which is the constructor.

The constructor is executed first, before the other methods (functions inside the class)

In the constructor function you must disable the shipping module when your customer is
buying 3 boxes or less:

if ($number_of_boxes <= 3) {
  $this->enabled = false;
}