Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Dear Janice Jewell,
Greetings! Thank you for posting in Microsoft Community. We are happy to help you.
Per your description, I understand you have budget restrictions and cannot purchase subscription version of Office product. You want to purchase Microsoft Office using the least expensive program and use it on three computers.
As far as I know, I'm sorry and I'm afraid there is no other one-time purchase Microsoft Office product that can be installed on three computers. I'm very sorry about it.
If you are willing, you may consider using the free online version of Office from personal OneDrive Online https://onedrive.live.com, you can sign in OneDrive by using a Microsoft account and then create files by clicking "+New". Please note that it has Word, Excel, PowerPoint but not Publisher.
If you don't have Microsoft account, you can create new one: How to create a new Microsoft account
You may also consider using other third-party Office product.
We will keep this thread open and welcome community members who have similar experience to share insights and suggestions here.
Thanks for your time and cooperation! Hope you have a nice day, stay safe and healthy.
Sincerely,
Tina | Microsoft Community Moderator