diff --git a/src/data/layers/dyes.tsx b/src/data/layers/dyes.tsx
index 11a1d8f..e6612f6 100644
--- a/src/data/layers/dyes.tsx
+++ b/src/data/layers/dyes.tsx
@@ -361,6 +361,7 @@ const layer = createLayer(id, function (this: BaseLayer) {
                     );
                 }),
                 onPurchase(cost?: DecimalSource) {
+                    buyable.amount.value = Decimal.add(buyable.amount.value, -1);
                     let buyMax = false;
                     switch (options.color) {
                         case "red":
diff --git a/src/data/layers/management.tsx b/src/data/layers/management.tsx
index 8fdf721..c7a91e0 100644
--- a/src/data/layers/management.tsx
+++ b/src/data/layers/management.tsx
@@ -1655,6 +1655,8 @@ const layer = createLayer(id, () => {
             );
         },
         onPurchase() {
+            // Lower amount first so costs are accurate, then re-add the purchase after
+            this.amount.value = Decimal.add(this.amount.value, -1);
             trees.logs.value = Decimal.sub(trees.logs.value, schoolCost.value.wood);
             coal.coal.value = Decimal.sub(coal.coal.value, schoolCost.value.coal);
             paper.paper.value = Decimal.sub(paper.paper.value, schoolCost.value.paper);
@@ -1718,6 +1720,8 @@ const layer = createLayer(id, () => {
             );
         },
         onPurchase() {
+            // Lower amount first so costs are accurate, then re-add the purchase after
+            this.amount.value = Decimal.add(this.amount.value, -1);
             trees.logs.value = Decimal.sub(trees.logs.value, classroomCost.value.wood);
             paper.paper.value = Decimal.sub(paper.paper.value, classroomCost.value.paper);
             boxes.boxes.value = Decimal.sub(boxes.boxes.value, classroomCost.value.boxes);
diff --git a/src/data/layers/routing.tsx b/src/data/layers/routing.tsx
index 7d1dd6a..970ba5e 100644
--- a/src/data/layers/routing.tsx
+++ b/src/data/layers/routing.tsx
@@ -654,6 +654,8 @@ const layer = createLayer(id, function (this: BaseLayer) {
                 );
             },
             onPurchase() {
+                // Lower amount first so costs are accurate, then re-add the purchase after
+                this.amount.value = Decimal.add(this.amount.value, -1);
                 management.classrooms.amount.value = Decimal.sub(
                     management.classrooms.amount.value,
                     unref(metaBuyables.classroom.cost ?? 0)
@@ -685,9 +687,6 @@ const layer = createLayer(id, function (this: BaseLayer) {
                     unref(metaBuyables.tick.cost ?? 0)
                 );
             },
-            onPurchase() {
-                this.amount.value = Decimal.add(this.amount.value, 1);
-            },
             display: jsx(() => (
                 <>
                     Upgrade computer
diff --git a/src/data/layers/toys.tsx b/src/data/layers/toys.tsx
index 370f43f..dacafcf 100644
--- a/src/data/layers/toys.tsx
+++ b/src/data/layers/toys.tsx
@@ -103,6 +103,8 @@ const layer = createLayer(id, function (this: BaseLayer) {
             );
         },
         onPurchase() {
+            // Lower amount first so costs are accurate, then re-add the purchase after
+            this.amount.value = Decimal.add(this.amount.value, -1);
             cloth.cloth.value = Decimal.sub(cloth.cloth.value, clothesCost.value.cloth);
             this.amount.value = Decimal.add(this.amount.value, 1);
             clothes.value = Decimal.add(clothes.value, 1);
@@ -135,6 +137,8 @@ const layer = createLayer(id, function (this: BaseLayer) {
             return woodenBlocksCost.value.wood.lte(trees.logs.value);
         },
         onPurchase() {
+            // Lower amount first so costs are accurate, then re-add the purchase after
+            this.amount.value = Decimal.add(this.amount.value, -1);
             trees.logs.value = Decimal.sub(trees.logs.value, woodenBlocksCost.value.wood);
             this.amount.value = Decimal.add(this.amount.value, 1);
             woodenBlocks.value = Decimal.add(woodenBlocks.value, 1);
@@ -194,6 +198,8 @@ const layer = createLayer(id, function (this: BaseLayer) {
             );
         },
         onPurchase() {
+            // Lower amount first so costs are accurate, then re-add the purchase after
+            this.amount.value = Decimal.add(this.amount.value, -1);
             metal.metal.value = Decimal.sub(metal.metal.value, trucksCost.value.metal);
             plastic.plastic.value = Decimal.sub(plastic.plastic.value, trucksCost.value.plastic);
             this.amount.value = Decimal.add(this.amount.value, 1);
@@ -291,7 +297,8 @@ const layer = createLayer(id, function (this: BaseLayer) {
     const milestone8 = createMilestone(() => ({
         display: {
             requirement: "6000 toys",
-            effectDisplay: "Running out of energy? Let's increase the limit! Multiply energy capacity by 1.4"
+            effectDisplay:
+                "Running out of energy? Let's increase the limit! Multiply energy capacity by 1.4"
         },
         shouldEarn: () => Decimal.gte(toySum.value, 6000),
         visibility: () =>
diff --git a/src/data/layers/wrapping-paper.tsx b/src/data/layers/wrapping-paper.tsx
index c267294..0837fe0 100644
--- a/src/data/layers/wrapping-paper.tsx
+++ b/src/data/layers/wrapping-paper.tsx
@@ -17,7 +17,7 @@ import { main } from "../projEntry";
 import { default as dyes, type enumColor } from "./dyes";
 import elves from "./elves";
 import toys from "./toys";
-import packing from "./packing"
+import packing from "./packing";
 
 const id = "wrappingPaper";
 const day = 15;
@@ -115,10 +115,6 @@ const layer = createLayer(id, () => {
                         if (Decimal.lt(resource.value, cost)) return false;
                     }
                     return true;
-                },
-                onPurchase() {
-                    buyable.amount.value = Decimal.add(buyable.amount.value, 1);
-                    // todo: stuff
                 }
             };
         });
@@ -260,22 +256,38 @@ const layer = createLayer(id, () => {
             ]
         })
     };
-    const packingBoost = computed(() => packing.packingMilestones.wrappingPaperBoost.earned.value ? 2 : 1)
+    const packingBoost = computed(() =>
+        packing.packingMilestones.wrappingPaperBoost.earned.value ? 2 : 1
+    );
     const boosts = {
         christmas1: computed(() =>
-            main.isMastery.value ? 1 : Decimal.add(wrappingPaper.christmas.buyable.amount.value, 1).mul(packingBoost.value)
+            main.isMastery.value
+                ? 1
+                : Decimal.add(wrappingPaper.christmas.buyable.amount.value, 1).mul(
+                      packingBoost.value
+                  )
         ), // Probably not the best way to do this, but it works
         rainbow1: computed(() =>
-            main.isMastery.value ? 1 : Decimal.pow(2, wrappingPaper.rainbow.buyable.amount.value).mul(packingBoost.value)
+            main.isMastery.value
+                ? 1
+                : Decimal.pow(2, wrappingPaper.rainbow.buyable.amount.value).mul(packingBoost.value)
         ),
         jazzy1: computed(() =>
-            main.isMastery.value ? 1 : Decimal.add(wrappingPaper.jazzy.buyable.amount.value, 1).mul(packingBoost.value)
+            main.isMastery.value
+                ? 1
+                : Decimal.add(wrappingPaper.jazzy.buyable.amount.value, 1).mul(packingBoost.value)
         ),
         sunshine1: computed(() =>
-            main.isMastery.value ? 1 : Decimal.add(wrappingPaper.sunshine.buyable.amount.value, 1).mul(packingBoost.value)
+            main.isMastery.value
+                ? 1
+                : Decimal.add(wrappingPaper.sunshine.buyable.amount.value, 1).mul(
+                      packingBoost.value
+                  )
         ),
         ocean1: computed(() =>
-            main.isMastery.value ? 1 : Decimal.pow(1.5, wrappingPaper.ocean.buyable.amount.value).mul(packingBoost.value)
+            main.isMastery.value
+                ? 1
+                : Decimal.pow(1.5, wrappingPaper.ocean.buyable.amount.value).mul(packingBoost.value)
         ),
         beach1: computed(() =>
             main.isMastery.value