Where do you buy your floors, Double pane windows, carpets, etc?

[Peter Turner]

Hello, 

I need to do some remodeling to a home and since it is the first time I am buying these materials I wanted to know if there is a better way to buy (cheaper) than just going through Home Depot or Lowes. 

I need to do floors and buy at least 1ksqft of Luxury Vinyl Tile and another 1k sqft of Carpet. (I hear that LVT is all the rage these days, but not sure if there is one that is preferred vs another one like glued vs snap together?)

Also need double pane insulated windows to go into existing wood frame. Home depot has them for like 100 bucks, not sure this can be beat, but I need at least 10. 

Need also to buy kitchen counter and bathroom sinks x 2. 

If you have any suggestions for alternatives to the big stores or if the big stores actually have the better prices and products, please let me know to help me narrow this down a little. 

Thanks a lot!