September is a good period for offering trainings to clients. In September, people have a more favourable attitude to education in general and most of the training courses start in September.

You may find convenient partnering with a University; some of the courses may not have been started yet, and facilities more easily available. You may host the training in student computer rooms.

To all the attendees a three months trial license should be offered. There is a chance that some of the free licences, would convert to annual subscriptions late in December, as Christmas gift.

I don’t know how the idea of the “One Month Free” software started – whether it has to do with purchase order cycle, or moon cycle.

From the end-user perspective, if the software is a “One-Off” application, one month trial is far too long. The user will  use the application and forget about you and your software. You should offer a shorter trial period, instead. On the other hand, if the software is a long term application, there’s no reason to limit the trial to 30 days. It would be better to implement functional restrictions. Even with limited features, the software will remain on your customer’s desktop, used from time to time.

I think the “one month free license” does not increase software sales, although many companies offer it.