Trading for a Spaceship from the Start

After getting a trading platform three thousand years in the future, everything in this world has become an antique, worth thousands of gold. But we also learned that three years later, aliens invaded, humanity fell, and the dark starry era began. This is an era of unprecedented change in tens of thousands of years. Shen Shi decided. Let's trade a space battleship first to calm down the panic. So Battleships come to the world from outer space! Global shock! The Starry Sky Era starts in advance!