$productUrl = Mage::getUrl('catalog/product/view', array('id' => $productId));
$categoryUrl = Mage::getUrl('catalog/category/view', array('id' => $categoryId));
$checkoutUrl = Mage::getUrl('checkout/cart');This code retrieves the URL for the checkout page, using the "checkout/cart" controller. The resulting $checkoutUrl can be used to create a link to the checkout page. Magento is the package library used for this code.