Adobe does give the option of buying a particular product's subscription for a month only. Check this link for all plans: https://creative.adobe.com/plans
For your requirement, you may select the 'monthly app' option under 'Single app'. That should work for you.
If you definitely only want it for 30 days and no longer, just download and install the free trial version.
That'll give you up to 30 days free use with no obligation to sign up.
Any longer and the month-by-month plan would be the next best option.
I've already downloaded the trial previously so will try the month by month plan. Thanks you.