I am still running Office (Home and Student) 2010 with no problems. I bought the disks for it years ago, in other words paid once. I have installed it on several different machines. You may be able to find a set of disks for sale somewhere. If you are familiar with MS Office and don't want to learn anything new, it might be worth considering. I only really use if for MS Word, and MS Powerpoint.
There is a lot of very reliable/stable free MS compatible stuff available now. If you are not using it for professional purposes, it is more than up to the job. If you are familiar with MS Office, these are reasonably easy to learn, there are only a few differences. These differences is that some of the tools that a 'power user' may want are not there.