Player trading

1. In-Game Economy vs Real Economy (Virtual Economy Gamification Tips)
2. Tradable vs Sellable (Virtual Economy Gamification Tips)
3. Player Trading vs Player Selling (Virtual Economy Gamification Tips)
4. Game Wealth vs Virtual Wealth (Virtual Economy Gamification Tips)
5. Tradable Items vs Non-Tradable Items (Virtual Economy Gamification Tips)
6. Virtual Wealth vs Real Wealth (Virtual Economy Gamification Tips)
7. Virtual Auction vs In-Game Auction (Virtual Economy Gamification Tips)