After you order the first item you will see a little truck next to some of the items you also might be interested in. That tells you it is the same warehouse as items you have in your cart. So that means that sometimes a lower cost item from a different warehouse might be more expensive then a higher priced item from the same warehouse because of freight. Then once you have your order set what I then do is go back and buy other items that I can add to the order that are from the same warehouses that may not add to the freight charge. These items might be oil/air filters, wiper blades, relays, brake pads, spark plugs/wires, etc. As long as the freight charge doesn't increase I consider it a good deal.
Of course if you don't drive many miles that may not be as important, but for me it makes sense.
I just placed an order an did just that. I started needing oil pan gaskets and timing chain gasket set [2 each]. Then I added front brake lines, front brake rotors and pads, wiper blades, oil filters. Then I added an air filter for my wife's Enclave and then oil/air/cabin filter for my daughter's KIA. The order was about $125.00 with about $27.00 of that in freight but look at all the stuff I got and will probably use in the next 6 months.