diff --git a/src/Models/Product.php b/src/Models/Product.php
index ff811838b..30d4469ce 100644
--- a/src/Models/Product.php
+++ b/src/Models/Product.php
@@ -7,6 +7,7 @@
 use Illuminate\Database\Eloquent\Relations\BelongsToMany;
 use Illuminate\Database\Eloquent\Relations\HasMany;
 use Illuminate\Database\Eloquent\Relations\HasOne;
+use Illuminate\Support\Arr;
 use Illuminate\Support\Collection;
 use Rapidez\Core\Facades\Rapidez;
 use Rapidez\Core\Models\Relations\BelongsToManyCallback;
@@ -241,7 +242,9 @@ public function getUnitPrice(int $quantity = 1, int $customerGroup = 0)
         // NOTE: We always need the option with the lowest matching value, *not* the one with the highest matching qty!
         // It wouldn't make sense to select a tier with a higher qty if the price is higher.
 
-        return $tierPrice ?? $this->price;
+        $prices = Arr::whereNotNull([$tierPrice, $this->price, $this->specialPrice]);
+
+        return $prices ? min($prices) : null;
     }
 
     public function getPrice(int $quantity = 1, int $customerGroup = 0)
diff --git a/src/Models/ProductTierPrice.php b/src/Models/ProductTierPrice.php
index 5d336a08a..f386a52b4 100644
--- a/src/Models/ProductTierPrice.php
+++ b/src/Models/ProductTierPrice.php
@@ -13,6 +13,8 @@ class ProductTierPrice extends Model
 
     protected $primaryKey = 'value_id';
 
+    protected $guarded = [];
+
     public function product(): BelongsTo
     {
         return $this->belongsTo(
diff --git a/tests/Unit/ProductPriceTest.php b/tests/Unit/ProductPriceTest.php
index 49dcf78d3..2c9c6b566 100644
--- a/tests/Unit/ProductPriceTest.php
+++ b/tests/Unit/ProductPriceTest.php
@@ -55,7 +55,51 @@ public function product_catalog_price_rules_apply()
     #[Test]
     public function product_can_have_tier_prices()
     {
-        $this->assertTrue(true);
-        // TODO: Base DB doesn't have tier prices. Test this some other way.
+        $product = Product::find(4);
+
+        $product->tierPrices()->create(['qty' => 2, 'value' => 50, 'website_id' => 1, 'all_groups' => 1, 'customer_group_id' => 0]);
+        $product->tierPrices()->create(['qty' => 5, 'value' => 40, 'website_id' => 1, 'all_groups' => 1, 'customer_group_id' => 0]);
+        $product->tierPrices()->create(['qty' => 10, 'value' => 35, 'website_id' => 1, 'all_groups' => 1, 'customer_group_id' => 0]);
+        $product->tierPrices()->create(['qty' => 15, 'value' => 40, 'website_id' => 1, 'all_groups' => 1, 'customer_group_id' => 0]);
+
+        $product->tierPrices()->create(['qty' => 1, 'value' => 43, 'website_id' => 1, 'all_groups' => 0, 'customer_group_id' => 2]);
+        $product->tierPrices()->create(['qty' => 5, 'value' => 39, 'website_id' => 1, 'all_groups' => 0, 'customer_group_id' => 2]);
+        $product->tierPrices()->create(['qty' => 15, 'value' => 34, 'website_id' => 1, 'all_groups' => 0, 'customer_group_id' => 2]);
+
+        $product->tierPrices()->create(['qty' => 20, 'value' => 30, 'website_id' => 0, 'all_groups' => 1, 'customer_group_id' => 0]);
+
+        // All groups
+        $this->assertEquals(45 * 4, $product->getPrice(4), 'Tier price for all groups, qty 4');
+        $this->assertEquals(40 * 5, $product->getPrice(5), 'Tier price for all groups, qty 5');
+        $this->assertEquals(35 * 12, $product->getPrice(12), 'Tier price for all groups, qty 12');
+        $this->assertEquals(35 * 15, $product->getPrice(15), 'Tier price for all groups, qty 15');
+        $this->assertEquals(30 * 23, $product->getPrice(23), 'Tier price for all groups, qty 23');
+
+        // Specifically customer group 2
+        $this->assertEquals(43 * 4, $product->getPrice(4, 2), 'Tier price for group 2, qty 4');
+        $this->assertEquals(39 * 5, $product->getPrice(5, 2), 'Tier price for group 2, qty 5');
+        $this->assertEquals(35 * 12, $product->getPrice(12, 2), 'Tier price for group 2, qty 12');
+        $this->assertEquals(34 * 15, $product->getPrice(15, 2), 'Tier price for group 2, qty 15');
+        $this->assertEquals(30 * 22, $product->getPrice(22, 2), 'Tier price for group 2, qty 22');
+
+        // This is technically not valid, but without creating a whole new website this is the best we can do in a unit test.
+        config()->set('rapidez.website', 0);
+        $this->assertEquals(45 * 15, $product->getPrice(15, 2), 'Tier price on website 0 for group 2, qty 15');
+        $this->assertEquals(45 * 15, $product->getPrice(15), 'Tier price on website 0 for all groups, qty 15');
+        $this->assertEquals(30 * 21, $product->getPrice(21), 'Tier price on website 0 for all groups, qty 21');
+    }
+
+    #[Test]
+    public function product_can_combine_tier_prices_and_special_price()
+    {
+        $product = Product::find(10);
+
+        $product->tierPrices()->create(['qty' => 5, 'value' => 30, 'website_id' => 1, 'all_groups' => 1, 'customer_group_id' => 0]);
+        $product->tierPrices()->create(['qty' => 10, 'value' => 20, 'website_id' => 1, 'all_groups' => 1, 'customer_group_id' => 0]);
+
+        // All groups
+        $this->assertEquals(24 * 4, $product->getPrice(4), 'Tier price (should be special price) for all groups, qty 4');
+        $this->assertEquals(24 * 5, $product->getPrice(5), 'Tier price (should be special price) for all groups, qty 5');
+        $this->assertEquals(20 * 12, $product->getPrice(12), 'Tier price for all groups, qty 12');
     }
 }