When sourcing steel gate doors, the price is primarily driven by material grade, surface treatment, and weight. You should prioritize hot-dip galvanized steel over cold-rolled steel to ensure long-term corrosion resistance, especially for outdoor applications. Always verify the wall thickness of the steel tubes (standard industrial grade is usually 2.0mm or higher) as thinner materials may reduce costs but compromise structural integrity. Additionally, check if the price includes high-quality hardware like heavy-duty hinges and industrial locks, which are critical for the gate's lifespan.