Let's see, I buy my dress shirts at Costco or Land's End. I buy my dress slacks at Amazon. Underwear and socks are usually from Costco. Ties are from whomever is having a sale. Most of my bow ties are from JC Penney. Rugby shirts and some casual wear from Amazon. Jeans and casual pants from Walmart or Target. Dress shoes are from Amazon.
I don't buy much any more in the way of clothes since I buy them and keep them until they wear out. I probably have 30 dress shirts and 10 pairs of dress slacks, and I wear them in rotation. I have over 150 ties, both conventional and bow tie. About 10 suits that I virtually never wear any more and about 10 blazers or sport coats. Some of my ties, suits and blazers are 30 years old, and were from the era of wearing a suit/blazer to the office every day. Now with business casual, I still wear a dress shirt, tie and dress slacks every work day and keep an emergency blazer in the office in case I need it. I am overdressed for my work environment, but that is how I like to dress in the office.
I have found that once I am solid with the sizes of a particular brand, Amazon is usually quicker, cheaper and has what I want in stock.