I have 3 major sources of purchases outside groceries: Amazon, eBay, and Walmart. Gets me what I need when I need it. Also provides competition and a way for little guys to operate against the big guys.
There are other channels I look at as well depending on the product: Etsy, Facebook live auctions, Craig’s List, traditional Yard Sales, and such.
My wife and daughters won’t buy clothes online and most groceries my wife is too picky to trust anyone else to do the selection. So those continue to be brick and mortar.
Basically the same here. I use Amazon the way people use the brick 'n mortar stores. Shop there, find what I want, check the reviews and then search for the same item on eBay. Usually find it and get free shipping, something you can't get on Amazon without going Prime.