I did a RockAuto order yesterday for my Jeep. I ordered a water pump, a water pump (heater hose connect) metal tube, an upper radiator hose, a radiator cap, and a resister block for my blower motor. Total cost, including shipping was $49.98.
Today I went to my local auto parts store to get the lower radiator hose (RA couldn't get a lower radiator hose into the order from the same warehouse) and the first store didn't have it in inventory. So I had to use more gas to go the next auto parts store and I found one for $26. That's for just the one hose. Had I bit the bullet and just ordered from two RA warehouses, I still would have saved money.
I will still use RockAuto for a lot of items, but yes, you have to carefully watch how many warehouses your products from.