diff --git a/test/common/ops/buy/buy.js b/test/common/ops/buy/buy.js
index 5ec36dfd3a..f203ae0cd9 100644
--- a/test/common/ops/buy/buy.js
+++ b/test/common/ops/buy/buy.js
@@ -142,4 +142,52 @@ describe('shared.ops.buy', () => {
     buy(user, {params: {key: 'potion'}, quantity: 2});
     expect(user.stats.hp).to.eql(50);
   });
+
+  it('errors if user supplies a non-numeric quantity', (done) => {
+    try {
+      buy(user, {
+        params: {
+          key: 'dilatoryDistress1',
+        },
+        type: 'quest',
+        quantity: 'bogle',
+      });
+    } catch (err) {
+      expect(err).to.be.an.instanceof(BadRequest);
+      expect(err.message).to.equal(errorMessage('invalidQuantity'));
+      done();
+    }
+  });
+
+  it('errors if user supplies a negative quantity', (done) => {
+    try {
+      buy(user, {
+        params: {
+          key: 'dilatoryDistress1',
+        },
+        type: 'quest',
+        quantity: -3,
+      });
+    } catch (err) {
+      expect(err).to.be.an.instanceof(BadRequest);
+      expect(err.message).to.equal(errorMessage('invalidQuantity'));
+      done();
+    }
+  });
+
+  it('errors if user supplies a decimal quantity', (done) => {
+    try {
+      buy(user, {
+        params: {
+          key: 'dilatoryDistress1',
+        },
+        type: 'quest',
+        quantity: 1.83,
+      });
+    } catch (err) {
+      expect(err).to.be.an.instanceof(BadRequest);
+      expect(err.message).to.equal(errorMessage('invalidQuantity'));
+      done();
+    }
+  });
 });
diff --git a/test/common/ops/buy/purchase.js b/test/common/ops/buy/purchase.js
index fd1ab65b48..9c3bb5233c 100644
--- a/test/common/ops/buy/purchase.js
+++ b/test/common/ops/buy/purchase.js
@@ -108,6 +108,47 @@ describe('shared.ops.purchase', () => {
         done();
       }
     });
+
+    it('returns error when user supplies a non-numeric quantity', (done) => {
+      let type = 'eggs';
+      let key = 'Wolf';
+
+      try {
+        purchase(user, {params: {type, key}, quantity: 'jamboree'}, analytics);
+      } catch (err) {
+        expect(err).to.be.an.instanceof(BadRequest);
+        expect(err.message).to.equal(i18n.t('invalidQuantity'));
+        done();
+      }
+    });
+
+    it('returns error when user supplies a negative quantity', (done) => {
+      let type = 'eggs';
+      let key = 'Wolf';
+      user.balance = 10;
+
+      try {
+        purchase(user, {params: {type, key}, quantity: -2}, analytics);
+      } catch (err) {
+        expect(err).to.be.an.instanceof(BadRequest);
+        expect(err.message).to.equal(i18n.t('invalidQuantity'));
+        done();
+      }
+    });
+
+    it('returns error when user supplies a decimal quantity', (done) => {
+      let type = 'eggs';
+      let key = 'Wolf';
+      user.balance = 10;
+
+      try {
+        purchase(user, {params: {type, key}, quantity: 2.9}, analytics);
+      } catch (err) {
+        expect(err).to.be.an.instanceof(BadRequest);
+        expect(err.message).to.equal(i18n.t('invalidQuantity'));
+        done();
+      }
+    });
   });
 
   context('successful purchase', () => {
diff --git a/website/client/components/shops/buyModal.vue b/website/client/components/shops/buyModal.vue
index fee9615707..83e2c0649d 100644
--- a/website/client/components/shops/buyModal.vue
+++ b/website/client/components/shops/buyModal.vue
@@ -48,7 +48,7 @@
             strong {{ $t('howManyToBuy') }}
           div(v-if='showAmountToBuy(item)')
             .box
-              input(type='number', min='0', v-model.number='selectedAmountToBuy')
+              input(type='number', min='0', step='1', v-model.number='selectedAmountToBuy')
             span(:class="{'notEnough': notEnoughCurrency}")
               span.svg-icon.inline.icon-32(aria-hidden="true", v-html="icons[getPriceClass()]")
               span.cost(:class="getPriceClass()") {{ item.value }}
@@ -71,7 +71,7 @@
         button.btn.btn-primary(
           @click="buyItem()",
           v-else,
-          :disabled='item.key === "gem" && gemsLeft === 0 || attemptingToPurchaseMoreGemsThanAreLeft',
+          :disabled='item.key === "gem" && gemsLeft === 0 || attemptingToPurchaseMoreGemsThanAreLeft || numberInvalid',
           :class="{'notEnough': !preventHealthPotion || !this.enoughCurrency(getPriceClass(), item.value * selectedAmountToBuy)}"
         ) {{ $t('buyNow') }}
 
@@ -260,6 +260,7 @@
   import * as Analytics from 'client/libs/analytics';
   import spellsMixin from 'client/mixins/spells';
   import planGemLimits from 'common/script/libs/planGemLimits';
+  import numberInvalid from 'client/mixins/numberInvalid';
 
   import svgClose from 'assets/svg/close.svg';
   import svgGold from 'assets/svg/gold.svg';
@@ -291,7 +292,7 @@
   ];
 
   export default {
-    mixins: [currencyMixin, notifications, spellsMixin, buyMixin],
+    mixins: [buyMixin, currencyMixin, notifications, numberInvalid, spellsMixin],
     components: {
       BalanceInfo,
       EquipmentAttributesGrid,
diff --git a/website/client/components/shops/quests/buyQuestModal.vue b/website/client/components/shops/quests/buyQuestModal.vue
index 11217d0912..f61e7138ba 100644
--- a/website/client/components/shops/quests/buyQuestModal.vue
+++ b/website/client/components/shops/quests/buyQuestModal.vue
@@ -22,7 +22,7 @@
           .how-many-to-buy
             strong {{ $t('howManyToBuy') }}
           .box
-            input(type='number', min='0', v-model.number='selectedAmountToBuy')
+            input(type='number', min='0', step='1', v-model.number='selectedAmountToBuy')
           span.svg-icon.inline.icon-32(aria-hidden="true", v-html="(priceType  === 'gems') ? icons.gem : icons.gold")
           span.value(:class="priceType") {{ item.value }}
 
@@ -34,7 +34,8 @@
         button.btn.btn-primary(
           @click="buyItem()",
           v-else,
-          :class="{'notEnough': !this.enoughCurrency(priceType, item.value * selectedAmountToBuy)}"
+          :class="{'notEnough': !this.enoughCurrency(priceType, item.value * selectedAmountToBuy)}",
+          :disabled='numberInvalid',
         ) {{ $t('buyNow') }}
 
     div.right-sidebar(v-if="item.drop")
@@ -207,12 +208,13 @@
   import QuestInfo from './questInfo.vue';
   import notifications from 'client/mixins/notifications';
   import buyMixin from 'client/mixins/buy';
+  import numberInvalid from 'client/mixins/numberInvalid';
 
   import questDialogDrops from './questDialogDrops';
   import questDialogContent from './questDialogContent';
 
   export default {
-    mixins: [currencyMixin, notifications, buyMixin],
+    mixins: [buyMixin, currencyMixin, notifications, numberInvalid],
     components: {
       BalanceInfo,
       QuestInfo,
@@ -309,7 +311,6 @@
             return `Unknown type: ${drop.type}`;
         }
       },
-
       purchaseGems () {
         this.$root.$emit('bv::show::modal', 'buy-gems');
       },
diff --git a/website/client/mixins/numberInvalid.js b/website/client/mixins/numberInvalid.js
new file mode 100644
index 0000000000..74db1d8be5
--- /dev/null
+++ b/website/client/mixins/numberInvalid.js
@@ -0,0 +1,7 @@
+export default {
+  computed: {
+    numberInvalid () {
+      return this.selectedAmountToBuy < 1 || !Number.isInteger(this.selectedAmountToBuy);
+    },
+  },
+};
diff --git a/website/common/errors/commonErrorMessages.js b/website/common/errors/commonErrorMessages.js
index 00a2d38fea..a9c4173405 100644
--- a/website/common/errors/commonErrorMessages.js
+++ b/website/common/errors/commonErrorMessages.js
@@ -9,6 +9,7 @@ module.exports = {
   itemNotFound: 'Item "<%= key %>" not found.',
   questNotFound: 'Quest "<%= key %>" not found.',
   spellNotFound: 'Skill "<%= spellId %>" not found.',
+  invalidQuantity: 'Quantity to purchase must be a positive whole number.',
   invalidTypeEquip: '"type" must be one of "equipped", "pet", "mount", "costume"',
   missingPetFoodFeed: '"pet" and "food" are required parameters.',
   missingEggHatchingPotion: '"egg" and "hatchingPotion" are required parameters.',
diff --git a/website/common/locales/en/npc.json b/website/common/locales/en/npc.json
index 3e02837d6c..754ed810b3 100644
--- a/website/common/locales/en/npc.json
+++ b/website/common/locales/en/npc.json
@@ -99,7 +99,7 @@
   "unlocked": "Items have been unlocked",
   "alreadyUnlocked": "Full set already unlocked.",
   "alreadyUnlockedPart": "Full set already partially unlocked.",
-  "invalidQuantity": "Quantity to purchase must be a number.",
+  "invalidQuantity": "Quantity to purchase must be a positive whole number.",
 
   "USD": "(USD)",
   "newStuff": "New Stuff by Bailey",
diff --git a/website/common/script/ops/buy/abstractBuyOperation.js b/website/common/script/ops/buy/abstractBuyOperation.js
index 85b9588f0a..0a6f7735dd 100644
--- a/website/common/script/ops/buy/abstractBuyOperation.js
+++ b/website/common/script/ops/buy/abstractBuyOperation.js
@@ -21,7 +21,7 @@ export class AbstractBuyOperation {
     let quantity = _get(req, 'quantity');
 
     this.quantity = quantity ? Number(quantity) : 1;
-    if (isNaN(this.quantity)) throw new BadRequest(this.i18n('invalidQuantity'));
+    if (this.quantity < 1 || !Number.isInteger(this.quantity)) throw new BadRequest(this.i18n('invalidQuantity'));
   }
 
   /**
diff --git a/website/common/script/ops/buy/purchase.js b/website/common/script/ops/buy/purchase.js
index 752ffed231..20975506f0 100644
--- a/website/common/script/ops/buy/purchase.js
+++ b/website/common/script/ops/buy/purchase.js
@@ -73,7 +73,7 @@ module.exports = function purchase (user, req = {}, analytics) {
   let key = get(req.params, 'key');
 
   let quantity = req.quantity ? Number(req.quantity) : 1;
-  if (isNaN(quantity)) throw new BadRequest(i18n.t('invalidQuantity', req.language));
+  if (quantity < 1 || !Number.isInteger(quantity)) throw new BadRequest(i18n.t('invalidQuantity', req.language));
 
   if (!type) {
     throw new BadRequest(i18n.t('typeRequired', req.language));