Upgrade your backpack
You can upgrade your backpack by giving the warehouse manager enough goda, or buy Backpack Expansion Equipment to upgrade it.
1. Upgrade your backpack by giving money to NPC.
1) The first upgrading costs 100,000 godas, which can add 10 more slots into your backpack (No level requirement)
2) The second upgrading costs 700,000 godas, which can add 10 more slots into your backpack (requires level 21)
3) The second upgrading costs 3,000,000 godas, which can add 10 more slots into your backpack (requires level 41)
4) The second upgrading costs 10,000,000 godas, which can add 10 more slots into your backpack (requires level 61)

2. Upgrading your backpack by using Backpack Expansion Equipment.
One Backpack Expansion Equipment can increase the number of slots by 10.
The price of one Backpack Expansion Equipment is 250 points in the online shop..