diff --git a/index.html b/index.html
index 601c6c5..d23728b 100644
--- a/index.html
+++ b/index.html
@@ -39,7 +39,7 @@
     <section class="game_section">
       <h2 class="section_title">Current Price</h2>
 
-      <p data-bind="cost_per_cup" data-format="currency"></p>
+      <p data-bind="price_per_cup" data-format="currency"></p>
 
       <button class="change_price_button">Change Price</button>
     </section>
diff --git a/index.js b/index.js
index f3dc02e..ade43fa 100644
--- a/index.js
+++ b/index.js
@@ -5,9 +5,11 @@
 
 import { init_game } from './game.js';
 import { sprites, cups, render, whenSpritesReady } from './canvasController.js';
+import { createReactiveState, updateBindings } from './binding.js';
 
 // Initialize game state
-let gameState = init_game();
+let gameState = createReactiveState(init_game());
+updateBindings(gameState);
 
 // Wait for all sprites to load, then render once
 whenSpritesReady(() => {
@@ -22,14 +24,20 @@ whenSpritesReady(() => {
 });
 
 // UI Elements
-const goShoppingBtn = document.querySelector('.go-shopping-btn');
+const goShoppingBtn = document.querySelector('.go_shopping_btn');
+const shoppingModal = document.querySelector('.shopping_modal');
+const shoppingModalClose = document.querySelector('.shopping_modal_close');
 
 // Event handlers
 if (goShoppingBtn) {
   goShoppingBtn.addEventListener('click', () => {
-    console.log('Go shopping clicked!');
-    // TODO: Open shopping modal/UI
+    console.log('hey');
+    shoppingModal.classList.add('open');
   });
+
+  shoppingModalClose.addEventListener('click', () => {
+    shoppingModal.classList.remove('open')
+  })
 }
 
 // Export for debugging in console
diff --git a/style.css b/style.css
index 7afb521..3ae4c68 100644
--- a/style.css
+++ b/style.css
@@ -65,7 +65,7 @@ canvas {
   pointer-events: none;
 }
 
-.go-shopping-btn {
+.go_shopping_btn {
   font-family: 'Fredoka', sans-serif;
   font-size: 16px;
   font-weight: 600;
@@ -81,13 +81,309 @@ canvas {
   display: block;
 }
 
-.go-shopping-btn:hover {
+.go_shopping_btn:hover {
   background: linear-gradient(180deg, #ffe066 0%, #FDB813 100%);
   transform: translateY(-2px);
   box-shadow: 0 6px 0 #3f7a33;
 }
 
-.go-shopping-btn:active {
+.go_shopping_btn:active {
+  transform: translateY(2px);
+  box-shadow: 0 2px 0 #3f7a33;
+}
+
+/* Shopping Modal */
+.shopping_modal {
+  display: none;
+  position: fixed;
+  top: 0;
+  left: 0;
+  width: 100%;
+  height: 100%;
+  background: rgba(0, 0, 0, 0.5);
+  z-index: 100;
+  align-items: center;
+  justify-content: center;
+}
+
+.shopping_modal.open {
+  display: flex;
+}
+
+.shopping_modal_content {
+  background-color: #FFF9E6;
+  border: 4px solid #8fd16a;
+  border-radius: 20px;
+  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
+  width: 400px;
+  max-width: 90%;
+}
+
+.shopping_modal_header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  padding: 16px 20px;
+  border-bottom: 2px solid #8fd16a;
+}
+
+.shopping_modal_title {
+  font-family: 'Fredoka', sans-serif;
+  font-size: 24px;
+  color: #5C4632;
+  margin: 0;
+}
+
+.shopping_modal_close {
+  font-size: 28px;
+  font-weight: bold;
+  color: #7A6146;
+  background: none;
+  border: none;
+  cursor: pointer;
+  line-height: 1;
+  padding: 0;
+}
+
+.shopping_modal_close:hover {
+  color: #5C4632;
+}
+
+.shopping_modal_body {
+  padding: 16px 20px;
+}
+
+.shop_item {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  padding: 12px 0;
+  border-bottom: 1px solid #e0d4c0;
+}
+
+.shop_item:last-child {
+  border-bottom: none;
+}
+
+.shop_item_name {
+  font-family: 'Fredoka', sans-serif;
+  font-size: 18px;
+  color: #5C4632;
+  flex: 1;
+}
+
+.shop_item_price {
+  font-family: 'Inter', sans-serif;
+  font-size: 14px;
+  color: #7A6146;
+  margin-right: 16px;
+}
+
+.shop_item_btn {
+  font-family: 'Fredoka', sans-serif;
+  font-size: 14px;
+  font-weight: 600;
+  background: linear-gradient(180deg, #8fd16a 0%, #7bc256 100%);
+  color: #fff;
+  border: 2px solid #3f7a33;
+  border-radius: 8px;
+  padding: 6px 16px;
+  cursor: pointer;
+  box-shadow: 0 3px 0 #3f7a33;
+  transition: all 0.1s ease;
+}
+
+.shop_item_btn:hover {
+  background: linear-gradient(180deg, #a5e07a 0%, #8fd16a 100%);
+  transform: translateY(-1px);
+  box-shadow: 0 4px 0 #3f7a33;
+}
+
+.shop_item_btn:active {
+  transform: translateY(2px);
+  box-shadow: 0 1px 0 #3f7a33;
+}
+
+/* Change Price Button */
+.change_price_button {
+  font-family: 'Fredoka', sans-serif;
+  font-size: 16px;
+  font-weight: 600;
+  background: linear-gradient(180deg, #FDB813 0%, #f5a800 100%);
+  color: #5C4632;
+  border: 3px solid #3f7a33;
+  border-radius: 12px;
+  padding: 10px 20px;
+  cursor: pointer;
+  box-shadow: 0 4px 0 #3f7a33;
+  transition: all 0.1s ease;
+  margin: 12px auto 0;
+  display: block;
+}
+
+.change_price_button:hover {
+  background: linear-gradient(180deg, #ffe066 0%, #FDB813 100%);
+  transform: translateY(-2px);
+  box-shadow: 0 6px 0 #3f7a33;
+}
+
+.change_price_button:active {
+  transform: translateY(2px);
+  box-shadow: 0 2px 0 #3f7a33;
+}
+
+/* Price Change Modal */
+.price_change_modal {
+  display: none;
+  position: fixed;
+  top: 0;
+  left: 0;
+  width: 100%;
+  height: 100%;
+  background: rgba(0, 0, 0, 0.5);
+  z-index: 100;
+  align-items: center;
+  justify-content: center;
+}
+
+.price_change_modal.open {
+  display: flex;
+}
+
+.price_change_modal_content {
+  background-color: #FFF9E6;
+  border: 4px solid #8fd16a;
+  border-radius: 20px;
+  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
+  width: 320px;
+  max-width: 90%;
+}
+
+.price_change_modal_header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  padding: 16px 20px;
+  border-bottom: 2px solid #8fd16a;
+}
+
+.price_change_modal_title {
+  font-family: 'Fredoka', sans-serif;
+  font-size: 24px;
+  color: #5C4632;
+  margin: 0;
+}
+
+.price_change_modal_close {
+  font-size: 28px;
+  font-weight: bold;
+  color: #7A6146;
+  background: none;
+  border: none;
+  cursor: pointer;
+  line-height: 1;
+  padding: 0;
+}
+
+.price_change_modal_close:hover {
+  color: #5C4632;
+}
+
+.price_change_modal_body {
+  padding: 20px;
+  text-align: center;
+}
+
+.price_change_hint {
+  font-family: 'Inter', sans-serif;
+  font-size: 14px;
+  color: #7A6146;
+  margin: 0 0 16px;
+}
+
+.price_input_group {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  margin-bottom: 16px;
+}
+
+.price_currency {
+  font-family: 'Fredoka', sans-serif;
+  font-size: 32px;
+  color: #5C4632;
+  margin-right: 4px;
+}
+
+.price_input {
+  font-family: 'Fredoka', sans-serif;
+  font-size: 32px;
+  font-weight: 600;
+  color: #5C4632;
+  background: #fff;
+  border: 3px solid #8fd16a;
+  border-radius: 12px;
+  padding: 8px 12px;
+  width: 120px;
+  text-align: center;
+  outline: none;
+}
+
+.price_input:focus {
+  border-color: #3f7a33;
+  box-shadow: 0 0 0 3px rgba(143, 209, 106, 0.3);
+}
+
+.price_presets {
+  display: flex;
+  gap: 8px;
+  justify-content: center;
+  margin-bottom: 20px;
+}
+
+.price_preset_btn {
+  font-family: 'Fredoka', sans-serif;
+  font-size: 14px;
+  font-weight: 500;
+  background: #fff;
+  color: #5C4632;
+  border: 2px solid #e0d4c0;
+  border-radius: 8px;
+  padding: 6px 12px;
+  cursor: pointer;
+  transition: all 0.1s ease;
+}
+
+.price_preset_btn:hover {
+  border-color: #8fd16a;
+  background: #f0ffe0;
+}
+
+.price_preset_btn:active {
+  transform: scale(0.95);
+}
+
+.price_change_save_btn {
+  font-family: 'Fredoka', sans-serif;
+  font-size: 16px;
+  font-weight: 600;
+  background: linear-gradient(180deg, #8fd16a 0%, #7bc256 100%);
+  color: #fff;
+  border: 3px solid #3f7a33;
+  border-radius: 12px;
+  padding: 10px 32px;
+  cursor: pointer;
+  box-shadow: 0 4px 0 #3f7a33;
+  transition: all 0.1s ease;
+}
+
+.price_change_save_btn:hover {
+  background: linear-gradient(180deg, #a5e07a 0%, #8fd16a 100%);
+  transform: translateY(-2px);
+  box-shadow: 0 6px 0 #3f7a33;
+}
+
+.price_change_save_btn:active {
   transform: translateY(2px);
   box-shadow: 0 2px 0 #3f7a33;
 }