That's an excellent and very important question! Living near the ocean is wonderful, but the salt air is brutal on metal. You're smart to think about this upfront. For a trash bin that won't rust near the ocean, you need to look for specific materials and features.
First and foremost, prioritize the material. The gold standard is Marine-Grade 316 Stainless Steel. It contains molybdenum, which provides exceptional resistance to saltwater corrosion. It's more expensive but will last for decades. Next, look for Powder-Coated Aluminum. Aluminum naturally resists rust, and a high-quality, thick powder coat adds an extra layer of protection against salt and UV rays. Avoid plain steel or thin, painted metals, as they will corrode quickly.
Beyond material, check the construction. Ensure all hardware (hinges, bolts) is also made of stainless steel or coated to prevent "galvanic corrosion." A tight-fitting lid is crucial to keep out salty moisture and rain. Consider a bin with drainage holes at the bottom to prevent water from pooling inside.
For maintenance, simply rinse it occasionally with fresh water to remove salt buildup. Avoid harsh abrasive cleaners that can damage protective coatings.
In short, focus on marine-grade stainless steel or heavily powder-coated aluminum for a durable, rust-free solution that can handle the beautiful but harsh coastal environment.