Brake kits: 4 piston or One ??

Same kit the ram man sells looks like to me. The Ram man was a bit lower priced, you can by the rotors at any auto parts store so I saved a bunch buying my own and saving on shipping. Did you look at my restoration thread Rainy ?

they all offer free shipping on all the different kits even the one that includes rotors, so how does that save on shipping ??