When sourcing HDPE, the price is heavily influenced by technical grades. You must specify the Melt Flow Index (MFI/MFR), which determines processing suitability (e.g., 0.1-1.0 g/10min for blow molding vs. 2.0-20 g/10min for injection molding). Additionally, verify the Density range (typically 0.941–0.967 g/cm³) and Tensile Strength at Yield. For specialized applications, ensure the material has UV stabilization or ESCR (Environmental Stress Crack Resistance) properties, as these additives will increase the base price.