I don't think you can find Office 2016 from a legitimate reseller- and it will soon be out of support. I recommend getting the newest version (Office 2021) so you have the longest period of support. If you have more than one computer, consider a subscription - it is good for multiple computers you use - the retail perpetual licenses are good for one computer and there is no upgrade discount.
The Home and Student version is the least expensive of the retail versions but does not include Outlook, only Word, Excel, and PowerPoint.