If you buy a PC, it will come with Microsoft Office pre-installed. However this might not be the optimal version for your needs (for example, college professors need their students to use the same version of Word when giving assignments).
If you’re buying Windows software, then keep in mind that Windows installation discs do not come with MS Office; check retailers like Amazon or Best Buy to find out whether they offer MS Office pre-installed on PCs before purchasing these items (if they don’t come bundled at purchase time).
Many non-PC devices like tablets and laptops do not include Microsoft Office in their retail packaging either; often times it can be downloaded through an app store for free or acquired.