If you are setting up a public space, park, or city sidewalk, you probably want an urban trash can that looks good for years. Sunlight can really wreck certain materials, causing them to turn yellow, crack, or just look old. I have tested and researched this a lot, and here is the honest answer: the best material for a durable urban trash can that will not fade in the sun is heavy-duty, rotomolded high-density polyethylene (HDPE) or powder-coated stainless steel.
Let me explain why. HDPE is a plastic, but not the cheap kind. Professional grade HDPE has UV inhibitors mixed right into the plastic. This means the color is not just a surface coat; it is part of the whole structure. I have seen HDPE bins sit in direct Texas sun for five years, and they still look bright. They do not rust, dent easily, or get brittle. For most city use, this is my top pick.
Stainless steel can also work well, but you need 300 series stainless steel (like 304) with a high-quality powder coating. The coating protects against fading, but if the coating chips, the metal underneath can still look fine for decades. However, stainless steel is heavier and more expensive. Also, in very hot climates, the metal gets surprisingly hot to the touch.
Avoid basic painted steel or galvanized steel without coatings. They always fade quickly and then rust. Avoid cheap polyethylene (like from a home discount store) because it will turn chalky and gray in one season. For an urban setting where you want no fading and high durability, rotomolded HDPE is your best bet. It is tough, lightweight, and stands up to both direct sun and rain without losing color. Good luck with your project.