For a basic, no-frills trash can in a back alley, you want something durable, simple, and easy to manage. My top suggestion is a classic round galvanized metal trash can. They're affordable, rust-resistant, and heavy enough not to tip over easily in windy alleys. A 32-gallon size is a good standard—big enough to hold a decent amount of waste but not so heavy that it's impossible to move when full.
If you need something larger or more heavy-duty for commercial use, consider a simple rectangular commercial bin, often made of durable plastic or metal. Look for one with a tight-fitting lid to deter pests. Avoid fancy features like foot pedals or intricate lids; a simple swing-top or lift-off lid is best for alley conditions where dirt and grime are common.
Place it on a hard, flat surface if possible, and make sure you or your waste service can easily access it for pickup. The key is functionality over form: a sturdy material, a secure lid, and a practical shape. That's all you really need.