I'm new to the forum and am really hoping to find a good answer to this question! I'm in the midst of a moderate sized home addition which includes a bathroom redo. Our builder expects us to order our bath products (sinks, faucets, tub, etc) from a local bath supply store at full retail. I am finding that I can search for these exact products on ebay or other online realtors for almost half the price. Is there a hidden difference in quality of these items, even if the model numbers are exactly the same? Who can explain the huge price difference between a kohler sink on ebay and the same sink on the kohler website? Any advice would be so, so greatly appreciated. Thanks.