I have 2 web sites and in 10 years they have generated only 1 sale. I only sell items at 99p on the other side. most of my sales are here. I used to have an amazon shop for my books and it did well but then there was the rise of the 1p book sellers and i couldnt compete. I ended up binning over 1000 books last christmas when we moved house. I have recently opened a store on a site that focuses on handmade items but it is too early to tell yet whether it will be worthwhile.
In pre-internet days I had both a market stall and a B&M shop. the market stall was great but the rates on the b&m shop were just too high and i only lasted 6 months