diff --git a/Helper/Cart.php b/Helper/Cart.php
new file mode 100644
index 0000000..d407e90
--- /dev/null
+++ b/Helper/Cart.php
@@ -0,0 +1,70 @@
+<?php
+
+/**
+ * @category  Crankycyclops
+ * @package   Crankycyclops_DiscountCodeUrl
+ * @author    James Colannino
+ * @copyright Copyright (c) 2019 James Colannino
+ * @license   https://www.gnu.org/licenses/gpl-3.0.en.html GPL v3
+ */
+
+namespace Crankycyclops\DiscountCodeUrl\Helper;
+
+class Cart extends \Magento\Framework\App\Helper\AbstractHelper {
+
+	/**
+	 * @var \Magento\Quote\Api\CartRepositoryInterface
+	 */
+	private $quoteRepository;
+
+	/**
+	 * @var \Magento\Framework\Message\ManagerInterface
+	 */
+	private $messageManager;
+
+	/************************************************************************/
+
+	/**
+	 * Constructor
+	 *
+	 * @param \Magento\Quote\Api\CartRepositoryInterface $quoteRepository
+	 * @param \Magento\Framework\Message\ManagerInterface $messageManager
+	 */
+	public function __construct(
+		\Magento\Quote\Api\CartRepositoryInterface $quoteRepository,
+		\Magento\Framework\Message\ManagerInterface $messageManager
+	) {
+		$this->quoteRepository = $quoteRepository;
+		$this->messageManager = $messageManager;
+	}
+
+	/************************************************************************/
+
+	public function applyCoupon(\Magento\Quote\Model\Quote $quote, string $coupon): void {
+
+		try {
+			$quote->setCouponCode($coupon);
+			$this->quoteRepository->save($quote->collectTotals());
+		}
+
+		catch (LocalizedException $e) {
+			$this->messageManager->addError(
+				__("Discount code <strong>$coupon</strong> couldn't be applied: " .
+					$e->getMessage())
+			);
+		}
+
+		catch (\Exception $e) {
+			$this->messageManager->addError(
+				__("Discount code <strong>$coupon</strong> couldn't be applied or is invalid")
+			);
+		}
+
+		if ($quote->getCouponCode() != $coupon) {
+			$this->messageManager->addError(
+				__("Discount code <strong>$coupon</strong> is invalid. Verify that it's correct and try again.")
+			);
+		}
+	}
+}
+
diff --git a/Observer/Discountcodeurl/CheckoutCartSaveAfter.php b/Observer/Discountcodeurl/CheckoutCartSaveAfter.php
index ad96715..ff7ee5b 100644
--- a/Observer/Discountcodeurl/CheckoutCartSaveAfter.php
+++ b/Observer/Discountcodeurl/CheckoutCartSaveAfter.php
@@ -17,45 +17,41 @@ class CheckoutCartSaveAfter implements \Magento\Framework\Event\ObserverInterfac
 	 */
 	private $config;
 
-	/**
-	 * @var \Magento\Quote\Api\CartRepositoryInterface
-	 */
-	private $quoteRepository;
-
 	/**
 	 * @var \Crankycyclops\DiscountCodeUrl\Helper\Cookie
 	 */
 	private $cookieHelper;
 
 	/**
-	 * @var \Magento\Framework\Message\ManagerInterface
+	 * @var \Crankycyclops\DiscountCodeUrl\Helper\Cart
 	 */
-	private $messageManager;
+	private $cartHelper;
 
 	/************************************************************************/
 
 	/**
 	 * Constructor
 	 *
+	 * @param \Crankycyclops\DiscountCodeUrl\Helper\Config $config
 	 * @param \Crankycyclops\DiscountCodeUrl\Helper\Cookie $cookieHelper
+	 * @param \Crankycyclops\DiscountCodeUrl\Helper\Cart $cartHelper
 	 */
 	public function __construct(
 		\Crankycyclops\DiscountCodeUrl\Helper\Config $config,
-		\Magento\Quote\Api\CartRepositoryInterface $quoteRepository,
 		\Crankycyclops\DiscountCodeUrl\Helper\Cookie $cookieHelper,
-		\Magento\Framework\Message\ManagerInterface $messageManager
+		\Crankycyclops\DiscountCodeUrl\Helper\Cart $cartHelper
 	) {
 		$this->config = $config;
-		$this->quoteRepository = $quoteRepository;
 		$this->cookieHelper = $cookieHelper;
-		$this->messageManager = $messageManager;
+		$this->cartHelper = $cartHelper;
 	}
 
 	/************************************************************************/
 
 	/**
 	 * If a coupon code was set in the URL at any point during the session,
-	 * apply it as soon as the cart is created.
+	 * apply it as soon as the cart is created and re-apply it every time it's
+	 * updated to keep the total price current.
 	 *
 	 * @param \Magento\Framework\Event\Observer $observer
 	 *
@@ -72,30 +68,7 @@ public function execute(\Magento\Framework\Event\Observer $observer): void {
 				$cart = $observer->getData('cart');
 
 				if ($cart) {
-
-					try {
-						$cart->getQuote()->setCouponCode($coupon);
-						$this->quoteRepository->save($cart->getQuote()->collectTotals());
-					}
-
-					catch (LocalizedException $e) {
-						$this->messageManager->addError(
-							__("Discount code <strong>$coupon</strong> couldn't be applied: " .
-								$e->getMessage())
-						);
-					}
-
-					catch (\Exception $e) {
-						$this->messageManager->addError(
-							__("Discount code <strong>$coupon</strong> couldn't be applied or is invalid")
-						);
-					}
-
-					if ($cart->getQuote()->getCouponCode() != $coupon) {
-						$this->messageManager->addError(
-							__("Discount code <strong>$coupon</strong> is invalid. Verify that it's correct and try again.")
-						);
-					}
+					$this->cartHelper->applyCoupon($cart->getQuote(), $coupon);
 				}
 			}
 		}
diff --git a/Plugin/Framework/App/FrontControllerInterface.php b/Plugin/Framework/App/FrontControllerInterface.php
index dd2eaca..b334807 100644
--- a/Plugin/Framework/App/FrontControllerInterface.php
+++ b/Plugin/Framework/App/FrontControllerInterface.php
@@ -27,6 +27,11 @@ class FrontControllerInterface {
 	 */
 	private $cookieHelper;
 
+	/**
+	 * @var \Crankycyclops\DiscountCodeUrl\Helper\Cart
+	 */
+	private $cartHelper;
+
 	/**
 	 * @var \Magento\SalesRule\Model\Coupon
 	 */
@@ -42,6 +47,11 @@ class FrontControllerInterface {
 	 */
 	private $registry;
 
+	/**
+	 * @var \Magento\Checkout\Model\Session
+	 */
+	private $checkoutSession;
+
 	/************************************************************************/
 
 	/**
@@ -50,24 +60,30 @@ class FrontControllerInterface {
 	 * @param \Magento\Framework\App\RequestInterface $request
 	 * @param \Crankycyclops\DiscountCodeUrl\Helper\Config $config
 	 * @param \Crankycyclops\DiscountCodeUrl\Helper\Cookie $cookieHelper
+	 * @param \Crankycyclops\DiscountCodeUrl\Helper\Cart $cartHelper
 	 * @param \Magento\SalesRule\Model\Coupon $couponModel
 	 * @param \Magento\SalesRule\Model\Rule $ruleModel
 	 * @param \Magento\Framework\Registry $registry
+	 * @param \Magento\Checkout\Model\Session $checkoutSession
 	 */
 	public function __construct(
 		\Magento\Framework\App\RequestInterface $request,
 		\Crankycyclops\DiscountCodeUrl\Helper\Config $config,
 		\Crankycyclops\DiscountCodeUrl\Helper\Cookie $cookieHelper,
+		\Crankycyclops\DiscountCodeUrl\Helper\Cart $cartHelper,
 		\Magento\SalesRule\Model\Coupon $couponModel,
 		\Magento\SalesRule\Model\Rule $ruleModel,
-		\Magento\Framework\Registry $registry
+		\Magento\Framework\Registry $registry,
+		\Magento\Checkout\Model\Session $checkoutSession
 	) {
 		$this->request = $request;
 		$this->config = $config;
 		$this->cookieHelper = $cookieHelper;
+		$this->cartHelper = $cartHelper;
 		$this->couponModel = $couponModel;
 		$this->ruleModel = $ruleModel;
 		$this->registry = $registry;
+		$this->checkoutSession = $checkoutSession;
 	}
 
 	/************************************************************************/
@@ -216,5 +232,41 @@ public function beforeDispatch(\Magento\Framework\App\FrontControllerInterface $
 			}
 		}
 	}
+
+	/************************************************************************/
+
+	/**
+	 * If a quote already exists, we need to apply the discount code to it
+	 * automatically (if possible) and before the response is rendered. This
+	 * covers us in the case that a user applies a discount code to the URL
+	 * after having a cart that's already full (which means the save cart
+	 * observer won't execute and therefore won't update the quote's price.) I
+	 * can't do this in beforeDispatch, because based on my own testing, it
+	 * seems that the session classes don't get populated until after
+	 * FrontController::dispatch() finishes.
+	 *
+	 * @param \Magento\Framework\App\FrontControllerInterface $subject (not used)
+	 * @param ResponseInterface|ResultInterface Return value of FrontController::dispatch()
+	 *
+	 * @return ResponseInterface|ResultInterface
+	 */
+	public function afterDispatch(\Magento\Framework\App\FrontControllerInterface $subject, $result) {
+
+		if ($this->config->isEnabled()) {
+
+			// If a quote already exists, apply the
+			// discount automatically (if possible)
+			$coupon = $this->registry->registry('crankycyclops_discounturl_coupon');
+
+			if ($coupon && $this->checkoutSession->hasQuote()) {
+				$this->cartHelper->applyCoupon(
+					$this->checkoutSession->getQuote(),
+					$coupon
+				);
+			}
+		}
+
+		return $result;
+	}
 }