Walmart gives 10%, but only on general merchandise and fresh produce, and any food item that comes from a vendor (Coke, Frito Lay, etc.. in other words, junk food). Does not work on clearance or if you do a price match. It covers tax and a little bit extra.
At my job now, selling appliance parts, we get *massive* discounts on parts – the other day I bought new drip pans for my stove. Retail would have been over $80. I paid around $7.
But then some other things like the air fresheners, flashlights, etc, we only get a few dollars off. I think it depends on what the markup is but I’m not sure.