Yesterday Microsoft announced that you can now purchase a license for Microsoft Office for Mac outright $150. There is no mystery to the fact that Microsoft prefers its customers move to the monthly plan rather than outright purchase. In that sense, this $150 version feels like a begrudging sale more than something that they actually want you to buy.
With the new $150 version you can only install the application on one Mac and it does not include access to the iOS versions. Purchasing Microsoft Office for Mac on a monthly basis is going to require an investment between $7 and $10 a month (depending on which version you buy). The gating issue is whether or not you have two macs or you want to use Microsoft office on your iPad. If the answer to either of those two questions is yes, you're going to need to purchase the subscription plan.
Somewhat related, Katie Floyd and I spent an hour and a half talking about the relative merits of competing word processors just this last weekend on Mac Power Users.