class Product { private $price; public function setPrice($price) { $this->price = $price; } public function getPrice() { return $this->price; } } $product = new Product(); $product->setPrice(50); echo $product->getPrice();In this example, we create a Product class with a private property `price`. We then create a method `setPrice` which takes a parameter and sets the `price` property. Finally, we call the `getPrice` method to retrieve the value of the `price` property and output it to the screen. This example code does not require any external package or library as it is using only core PHP functions. However, if the application requires more advanced pricing or currency conversion functionality, external packages or libraries, such as the Money PHP library, can be used.