The automatic tool changer swaps tools from a carousel or chain so a program runs many operations unattended. Capacity (number of pockets) and change time affect throughput and value. A full, working tool package that conveys with the machine adds real money.
See every Vertical Machining Centers in the reference library, by make and model.
How this affects buying and selling: read The Gauge, or value any machine free at The Machine Blue Book.