When sourcing Sodium Hydroxide, the price is primarily driven by purity levels (typically 99% for flakes/pearls and 32%-50% for liquid lye). You must verify the chemical composition, specifically the Sodium Carbonate (Na2CO3) and Sodium Chloride (NaCl) content, as lower impurity levels often command a premium price. For industrial applications, ensure the product meets ISO 9001 standards, while food-grade or pharmaceutical-grade requirements must adhere to FCC or BP/USP monographs, which significantly impacts the cost structure.