In my experience, going to Microsoft is a pricey option, since there are many deals to be found on third party shops.
I'm not sure where you are in the world, but occasionally, I have had luck also going to the PC manufacturer's site to see if there's any deals once you decide on a computer. I think the Microsoft site is a nice place to start but I would recommend making a list of your core things you want in a PC and go through them to see what computers match that list and then consider your price range.