The price of hollow drill bits is primarily determined by the material composition and coating. High-Speed Steel (HSS) bits are cost-effective for general metalwork, while Tungsten Carbide Tipped (TCT) bits command a higher price due to their ability to cut through harder materials like stainless steel at higher speeds. Additionally, the cutting depth (typically 25mm, 35mm, or 50mm) and the shank type (Weldon, Universal, or Fein Quick-In) significantly impact the unit cost. Buyers should ensure the hardness rating (HRC) aligns with their specific application to avoid premature tool failure.