Costco Vs. Everyone else for Flooring, Appliances, Bedding, etc...

Hi All,

First time Homeowner here (Closing in January anyways) I'm shopping for Mattresses, washer&Dryer, and Flooring.

Is there any other places I should be looking for these? I swear by costco for things like tires, I'm looking for the best value (Price * Quality) Thanks in advance for any suggestions/confirmation!