Hey, great question! I totally get the need to find something that's both kind to your wallet and built to last outdoors. Based on my experience and research, here's the scoop.
For the absolute best value, I'd point you towards heavy-duty plastic bins, specifically those made from resin. They are the champions of the affordable-and-durable category. Look for keywords like "all-weather," "UV-resistant," or "rotomolded" in the product description. These are designed to handle sun, rain, and temperature swings without cracking, fading, or becoming brittle quickly. Brands like Rubbermaid or simple store brands often have excellent options in the $25-$50 range.
A 32-gallon or 44-gallon size is usually the sweet spot—big enough to be useful but not so huge it becomes unwieldy or overly expensive. Make sure it has a secure, tight-fitting lid to keep pests out and odors contained. A lid that flips open with a foot pedal is a huge plus for convenience.
While metal bins (like galvanized steel) are incredibly sturdy, they tend to be pricier and can rust over time if the coating chips. For a very limited budget, plastic/resin is the way to go. You might also check local hardware stores or big-box retailers' websites for sales on their in-house brands.
In short: Your best bet is a UV-resistant, rotomolded plastic/resin trash can with a secure lid, in a mid-size capacity. It won't break the bank upfront and will serve you well for several seasons with proper care. Happy hunting