lightroom [for only one month]

As far as I know the special photography subscription of Photoshop and Lightroom requires a one year contract

Cloud Plans https://creative.adobe.com/plans

-Subscription Terms https://www.adobe.com/misc/subscription_terms.html

-Purchasing FAQ https://forums.adobe.com/thread/1926340

Or, buy the serial number program for a one time fee

Buy Lightroom 6 https://helpx.adobe.com/creative-cloud/help/download-install-single-app-Lightroom-6.html

-Lightroom serial number will work on both Windows and Mac versions https://forums.adobe.com/thread/2179765