diff --git a/index.html b/index.html
index 2597e46..de01d15 100644
--- a/index.html
+++ b/index.html
@@ -59,6 +59,11 @@
         <label>Beskrivning av platsen <textarea name="location_description" required maxlength="2000" rows="4"></textarea></label>
         <label>Person du kan möta <input name="npc_name" required maxlength="120"></label>
         <label>Om personen <textarea name="npc_biography" required maxlength="2000" rows="4"></textarea></label>
+        <h3>Förslag på startläge</h3>
+        <p>Startpengar och varan är bara förslag. De sparas först när du redigerat och godkänt dem.</p>
+        <label>Startsaldo i kronor <input name="starting_balance_sek" type="number" min="0" step="1" required></label>
+        <label>En vara som går att köpa här <input name="offer_name" required maxlength="120"></label>
+        <label>Pris i hela kronor <input name="offer_price_sek" type="number" min="1" step="1" required></label>
         <div class="row"><button type="submit">Godkänn och börja spela</button><button id="discard-world-draft" type="button">Gör ett nytt förslag</button></div>
       </form>
     </section>
@@ -68,6 +73,15 @@
         <h3 id="place-heading"></h3><p id="place-description"></p>
         <h3 id="npc-heading"></h3><p id="npc-description"></p>
         <h3 id="player-heading"></h3><p id="player-biography"></p>
+        <h3>Ekonomi och ägodelar</h3>
+        <p>Saldo: <span id="balance"></span> kr</p>
+        <ul id="inventory" aria-label="Dina ägodelar"></ul>
+      </section>
+      <section class="card" id="shop" aria-labelledby="shop-heading" hidden>
+        <h3 id="shop-heading">Köp på platsen</h3>
+        <p><span id="offer-description"></span></p>
+        <p id="offer-affordability"></p>
+        <button id="buy-offer" type="button">Köp</button>
       </section>
       <section class="card" aria-labelledby="conversation-heading">
         <h3 id="conversation-heading">Samtal</h3>
@@ -125,6 +139,21 @@
       document.querySelector('#message-label').firstChild.textContent = `Skriv till ${world.npc.name} `;
       document.querySelector('#player-heading').textContent = `${gameState.character.name}, ${gameState.character.age} år`;
       document.querySelector('#player-biography').textContent = gameState.character.biography;
+      document.querySelector('#balance').textContent = (world.balance_sek ?? 0).toLocaleString('sv-SE');
+      const inventory = document.querySelector('#inventory');
+      inventory.replaceChildren(...(world.inventory ?? []).map((item) => {
+        const entry = document.createElement('li');
+        entry.textContent = `${item.name}: ${item.quantity}`;
+        return entry;
+      }));
+      const shop = document.querySelector('#shop');
+      shop.hidden = !world.offer;
+      if (world.offer) {
+        document.querySelector('#offer-description').textContent = `${world.offer.name} — ${world.offer.price_sek.toLocaleString('sv-SE')} kr`;
+        document.querySelector('#buy-offer').disabled = (world.balance_sek ?? 0) < world.offer.price_sek;
+        document.querySelector('#offer-affordability').textContent = (world.balance_sek ?? 0) < world.offer.price_sek ? 'Du har inte tillräckligt saldo för det här köpet.' : '';
+        document.querySelector('#buy-offer').setAttribute('aria-label', `Köp ${world.offer.name} för ${world.offer.price_sek} kronor`);
+      }
       renderConversation(await request('/api/npc/conversation'), world.npc.name);
     }
     document.querySelector('#auth-form').addEventListener('submit', async (event) => {
@@ -148,7 +177,7 @@
       try {
         const proposal = await request('/api/world/draft', {method:'POST',headers:{'content-type':'application/json'},body:JSON.stringify({idea:data.get('idea')})});
         const form = document.querySelector('#world-draft-form');
-        for (const key of ['name','location_name','location_description','npc_name','npc_biography']) form.elements[key].value = proposal[key];
+        for (const key of ['name','location_name','location_description','npc_name','npc_biography','starting_balance_sek','offer_name','offer_price_sek']) form.elements[key].value = proposal[key];
         form.hidden = false; status.textContent='Förslaget är klart. Granska och redigera det innan du godkänner.';
       } catch(error) { status.textContent=`Kunde inte skapa ett förslag: ${error.message}`; }
     });
@@ -158,7 +187,10 @@
     document.querySelector('#world-draft-form').addEventListener('submit', async (event) => {
       event.preventDefault(); const data = new FormData(event.currentTarget); status.textContent='Sparar din godkända värld…';
       try {
-        await request('/api/world', {method:'POST',headers:{'content-type':'application/json'},body:JSON.stringify(Object.fromEntries(data.entries()))});
+        const approval = Object.fromEntries(data.entries());
+        approval.starting_balance_sek = Number(approval.starting_balance_sek);
+        approval.offer_price_sek = Number(approval.offer_price_sek);
+        await request('/api/world', {method:'POST',headers:{'content-type':'application/json'},body:JSON.stringify(approval)});
         await openGame(); status.textContent='Din värld har sparats.';
       } catch(error) { status.textContent=`Kunde inte spara världen: ${error.message}`; }
     });
@@ -168,6 +200,27 @@
       try { const result=await request('/api/npc/messages',{method:'POST',headers:{'content-type':'application/json'},body:JSON.stringify({message,idempotency_key:crypto.randomUUID()})}); field.value=''; await openGame(); status.textContent='Samtalet har sparats.'; }
       catch(error){status.textContent=`Samtalet kunde inte skickas: ${error.message}`;}
     });
+    document.querySelector('#buy-offer').addEventListener('click', async () => {
+      if (!gameState?.world?.offer) return;
+      const world = gameState.world;
+      const storageKey = `pending-purchase:${world.id}:${world.offer.id}`;
+      const idempotencyKey = sessionStorage.getItem(storageKey) || crypto.randomUUID();
+      sessionStorage.setItem(storageKey, idempotencyKey);
+      const button = document.querySelector('#buy-offer');
+      button.disabled = true;
+      status.textContent = 'Genomför köpet…';
+      try {
+        await request('/api/purchases', {method:'POST',headers:{'content-type':'application/json'},body:JSON.stringify({offer_id:world.offer.id,expected_world_version:world.version,idempotency_key:idempotencyKey})});
+        sessionStorage.removeItem(storageKey);
+      } catch(error) {
+        button.disabled = false;
+        status.textContent = `Köpet kunde inte genomföras: ${error.message}`;
+        return;
+      }
+      try {
+        await openGame(); status.textContent = 'Köpet är sparat i din värld.';
+      } catch(error) { status.textContent = 'Köpet är sparat. Världen kunde inte läsas in just nu; ladda om sidan för att visa det.'; }
+    });
     document.querySelector('#logout').addEventListener('click', async () => { try { await request('/api/logout',{method:'POST'}); showAuth(); status.textContent='Du har loggat ut.'; } catch(error){status.textContent=`Kunde inte logga ut: ${error.message}`;} });
     request('/api/me').then(async () => { await openGame(); status.textContent='Din sparade spelvärld har lästs in.'; }).catch(() => { showAuth(); });
   </script>
diff --git a/scripts/check-frontend.sh b/scripts/check-frontend.sh
index e81c171..b4bc54e 100755
--- a/scripts/check-frontend.sh
+++ b/scripts/check-frontend.sh
@@ -8,6 +8,8 @@ grep -q 'id="frontend-version">__FRONTEND_VERSION__' index.html
 grep -q "request('/version')" index.html
 grep -q 'id="api-version"' index.html
 grep -Fq "credentials: 'same-origin'" index.html
+grep -q 'Köp på platsen' index.html
+grep -q "request('/api/purchases'" index.html
 grep -q 'location = /healthz' nginx/default.conf
 
 echo 'Frontend source checks passed.'