I think they do bulk sales. The more you buy the cheaper they sell it. (Per item. Cuz 10,000 of something is a whole lot more expensive than one item. Even at Grainger's individual sale price.)
Otherwise I can't figure out how they stay in business selling stuff at such ripoff prices.
Btw, I own one of their books. Number 404. I forget what year. It's huge! Over 4000 pages!
If I were to buy 5,000 M250R2s from the distributor I got my first one at (M2RR25S0A2GMS3358), it would cost me $970,000 plus tax. Now, I tried an experiment where I "bulk ordered" from Grainger and added 5,000 of the same fixture to my Grainger cart, and the image was my subtotal before tax.
As you can see, I am paying $1,000,000 more dollars ordering from Ripoff Grainger than if I were to order through my original distributor (Winlectric)
Winlectric - 1=$194.00
Grainger - 1=$379.75
So in conclusion, nope, you don't save any 💰 by buying in bulk from Grainger. Which takes us back to the original question, WHO keeps them in business?