Entirely free, both in terms of cost and speech wise, 7-Zip compresses files to some of the smallest around. It can create zip files and open – well, a plethora of formats. There’s a stable version and a beta for both 32-bit and 64-bit Windows, and it allows you to open any supported file with its file manager (which will be familiar if you’ve ever seen any of the commercial ZIP utilities), and to extract files directly to a new directory, or to create them from a selection you’ve got on screen.