The cheapest way to build a large spread is to buy used, especially immediately following the hunting season.
If you want brand-new decoys, these sites specialize in high-volume or "economy" lines: How To Get Decoys For CHEAP cheapest place to buy duck decoys
: Look for local waterfowl-specific trade groups. You can often find used mallard decoys for significantly less than retail—sometimes as low as $50–$125 for two dozen. The cheapest way to build a large spread