Calculate the total cost to upgrade your item based on real market prices
Note: All calculations are based on +1 items stored in NPC:
• +0 → +1 = 2× +1
• +1 → +2 = 2× +1
• +2 → +3 = 6× +1
• +3 → +4 = 18× +1
• +4 → +5 = 54× +1
• And so on following the progression...