diff --git a/src/ship/items/inventory.rs b/src/ship/items/inventory.rs
index a44c97d..5bb5c19 100644
--- a/src/ship/items/inventory.rs
+++ b/src/ship/items/inventory.rs
@@ -93,10 +93,16 @@ pub enum YesThereIsSpace {
     ExistingStack,
 }
 
+#[derive(Debug, Clone)]
+pub enum NoThereIsNotSpace {
+    FullStack,
+    FullInventory,
+}
+
 #[derive(Debug, Clone)]
 pub enum SpaceForStack {
     Yes(YesThereIsSpace),
-    No,
+    No(NoThereIsNotSpace),
 }
 
 impl InventoryItem {
@@ -470,7 +476,7 @@ impl CharacterInventory {
                     SpaceForStack::Yes(YesThereIsSpace::ExistingStack)
                 }
                 else {
-                    SpaceForStack::No
+                    SpaceForStack::No(NoThereIsNotSpace::FullStack)
                 }
             }
             None => {
@@ -478,7 +484,7 @@ impl CharacterInventory {
                     SpaceForStack::Yes(YesThereIsSpace::NewStack)
                 }
                 else {
-                    SpaceForStack::No
+                    SpaceForStack::No(NoThereIsNotSpace::FullInventory)
                 }
             }
         }
diff --git a/src/ship/items/manager.rs b/src/ship/items/manager.rs
index 143fd26..3050432 100644
--- a/src/ship/items/manager.rs
+++ b/src/ship/items/manager.rs
@@ -15,6 +15,7 @@ use crate::ship::trade::TradeItem;
 use crate::ship::drops::{ItemDrop, ItemDropType};
 use crate::ship::location::{AreaClient, RoomId};
 use crate::ship::shops::ShopItem;
+use crate::ship::packet::handler::trade::TradeError;
 
 use crate::ship::items::bank::*;
 use crate::ship::items::floor::*;
@@ -329,7 +330,7 @@ impl ItemManager {
                                 }));
                                 TriggerCreateItem::No
                             },
-                            SpaceForStack::No => {
+                            SpaceForStack::No(_) => {
                                 return Err(ItemManagerError::CouldNotAddToInventory(*item_id).into());
                             },
                         }
@@ -945,9 +946,48 @@ impl ItemManager {
                 let p1_inventory = it.manager.get_character_inventory(p1.1)?;
                 let p2_inventory = it.manager.get_character_inventory(p2.1)?;
 
-                //TODO: inv-selftrade+othertrade <= 30
-                //if p1_inventory
-
+                [(p2_inventory, p1_inventory, p2.2), (p1_inventory, p2_inventory, p1.2)].iter()
+                    .map(|(src_inventory, dest_inventory, to_trade)| {
+                        to_trade
+                            .iter()
+                            .try_fold(dest_inventory.count(), |acc, item| {
+                                match item {
+                                    TradeItem::Individual(..) => {
+                                        if acc >= 30 {
+                                            Err(TradeError::NoInventorySpace)
+                                        }
+                                        else {
+                                            Ok(acc + 1)
+                                        }
+                                    },
+                                    TradeItem::Stacked(item_id, amount) => {
+                                        let stacked_inventory_item = src_inventory
+                                            .get_item_by_id(*item_id)
+                                            .ok_or_else(|| TradeError::InvalidItemId(*item_id))?
+                                            .stacked()
+                                            .ok_or_else(|| TradeError::InvalidItemId(*item_id))?;
+                                        match dest_inventory.space_for_stacked_item(&stacked_inventory_item.tool, *amount) {
+                                            SpaceForStack::Yes(YesThereIsSpace::ExistingStack) => {
+                                                Ok(acc)
+                                            },
+                                            SpaceForStack::Yes(YesThereIsSpace::NewStack) => {
+                                                Ok(acc + 1)
+                                            },
+                                            SpaceForStack::No(NoThereIsNotSpace::FullStack) => {
+                                                Err(TradeError::NoStackSpace)
+                                            },
+                                            SpaceForStack::No(NoThereIsNotSpace::FullInventory) => {
+                                                Err(TradeError::NoInventorySpace)
+                                            },
+                                        }
+                                    },
+                                    TradeItem::Meseta(..) => {
+                                        Ok(acc)
+                                    }
+                                }
+                            })
+                    })
+                    .collect::<Result<Vec<_>, _>>()?;
 
                 let trade_items = [(p1, p2, p1_inventory, p2_inventory), (p2, p1, p2_inventory, p1_inventory)]
                     .map(|(src_client, dest_client, src_inventory, dest_inventory)| {