Every print job has setup: file prep, plate or screen, machine setup, and calibration. That cost is largely fixed whether you run 100 or 1,000 pieces. It is why short runs cost more per unit.
What setup includes
Prepress checks the file and prepares it for the press. For offset, a plate is made; for digital, the file is queued and calibrated. The press is set up for size, substrate, and ink. This labor and material is the same for 100 or 1,000.
Why it is fixed
You cannot run the job without prep and makeready. Spreading that cost over more units lowers the per-unit price. Small runs absorb the full setup in fewer units; bulk runs spread it.
What to expect
• Setup may be itemized or folded into the unit price.
• Reorders of the same job may have lower setup if plates or files are reused.
• Changing the file or specs usually means setup again.
Common mistake
Expecting "no setup" for a small run. The work still happens. Some shops fold it into the price; others line-item it. Either way, you are paying for it.