Does anybody know the best/cheap reloading recipe?
That depends on the hull.
Shotgun hulls are shaped differently inside by each manufacturer, and their volume and construction varies far more than metallic/brass cartridges. In addition, wads have differing gas seals and powder cup volumes. This is why shot shell reloading recipes are literally wad-and-hull dependent.
You have to pick your hull first, then find a suitable wad, and then pick a powder and primer.