At Home Depot - I know for wood if there is a defect and it'll be marked with the specific color for discount, but I didn't know that on open bagged items you get 50% off.
If you find anything open like mulch, soil, rocks - ask an employee how much would the item be. Today, I learned it's 50% off!
On this pallet there were miscellaneous outdoor items (soil, patio paver base, and mulch)
I bought 4 bags of mulch normally $3.48 each for only $1.74 each. Nothing wrong with the mulch at all, just a tiny bit spilled out, but over 90-95% left. When I got to the cashier, I asked for tape so it wouldn't be a mess in my trunk.
Source: Personal experience