Years ago, when I was working, I had several opportunities to help during major installs, etc., at the Walmart headquarters in Bentonville, AK. Walmart has a huge hall at the front of its offices, where the salesmen from dozens of companies line up every day to meet with the Walmart buyers. In the vast majority of cases, Walmart buys huge quantities of the "branded" products, at a substantially reduced price, under it's own "Great Value" brand. The Only difference is the label being applied to the container at the factory.
We used to get a chuckle watching these salesmen come in during the morning...with big smiles, and full of hope for making a huge profit on their sales. Then, later in the day, they left, looking downtrodden and disappointed at the fact that they were only able to make a 2 or 3 percent profit, instead of the 10 to 20% profit the "brand" would sell for.