diff --git a/src/applications/phortune/product/PhortuneSubscriptionProduct.php b/src/applications/phortune/product/PhortuneSubscriptionProduct.php
index dc1aed421b..9b83cbf6cb 100644
--- a/src/applications/phortune/product/PhortuneSubscriptionProduct.php
+++ b/src/applications/phortune/product/PhortuneSubscriptionProduct.php
@@ -43,6 +43,7 @@ final class PhortuneSubscriptionProduct
   }
 
   public function getPriceAsCurrency(PhortuneProduct $product) {
+    // Prices are calculated by the SubscriptionImplementation.
     return PhortuneCurrency::newEmptyCurrency();
   }
 
diff --git a/src/applications/phortune/storage/PhortuneSubscription.php b/src/applications/phortune/storage/PhortuneSubscription.php
index 51ac283668..dedc0010fc 100644
--- a/src/applications/phortune/storage/PhortuneSubscription.php
+++ b/src/applications/phortune/storage/PhortuneSubscription.php
@@ -183,6 +183,13 @@ final class PhortuneSubscription extends PhortuneDAO
     return "/phortune/merchant/{$merchant_id}/subscription/view/{$id}/";
   }
 
+  public function getCostForBillingPeriodAsCurrency($start_epoch, $end_epoch) {
+    return $this->getImplementation()->getCostForBillingPeriodAsCurrency(
+      $this,
+      $start_epoch,
+      $end_epoch);
+  }
+
 
 /* -(  PhabricatorPolicyInterface  )----------------------------------------- */
 
diff --git a/src/applications/phortune/subscription/PhortuneSubscriptionImplementation.php b/src/applications/phortune/subscription/PhortuneSubscriptionImplementation.php
index 8e7559c2e9..0abc346a85 100644
--- a/src/applications/phortune/subscription/PhortuneSubscriptionImplementation.php
+++ b/src/applications/phortune/subscription/PhortuneSubscriptionImplementation.php
@@ -8,6 +8,10 @@ abstract class PhortuneSubscriptionImplementation {
 
   abstract public function getRef();
   abstract public function getName(PhortuneSubscription $subscription);
+  abstract public function getCostForBillingPeriodAsCurrency(
+    PhortuneSubscription $subscription,
+    $start_epoch,
+    $end_epoch);
 
   protected function getContentSource() {
     return PhabricatorContentSource::newForSource(
diff --git a/src/applications/phortune/worker/PhortuneSubscriptionWorker.php b/src/applications/phortune/worker/PhortuneSubscriptionWorker.php
index 8c9809042f..c59bef0422 100644
--- a/src/applications/phortune/worker/PhortuneSubscriptionWorker.php
+++ b/src/applications/phortune/worker/PhortuneSubscriptionWorker.php
@@ -42,9 +42,9 @@ final class PhortuneSubscriptionWorker extends PhabricatorWorker {
 
     $purchase = $cart->newPurchase($actor, $product);
 
-    // TODO: Consider allowing subscriptions to cost an amount other than one
-    // dollar and twenty-three cents.
-    $currency = PhortuneCurrency::newFromUserInput($actor, '1.23 USD');
+    $currency = $subscription->getCostForBillingPeriodAsCurrency(
+      $last_epoch,
+      $next_epoch);
 
     $purchase
       ->setBasePriceAsCurrency($currency)