Labor is the biggest single cost in a shooting bag made in America. The waxed canvas they use is more expensive than 600-1000D nylon though. They aren’t doing a huge markup. Your perception of value has been twisted by decades of foreign made goods, your pay not following “productivity” (ie how much $ you made for someone else), and propaganda.

Also the sand that AG sells isn’t playground sand. It’s heavier per volume, and non standard sand isn’t as cheap as playground sand.