Hi,
You have 2 offers:
- monthly payment for $19.90 per month: it gives you access to all the software and to Substance Source, as long as you are subscribed
- perpetual license + 12 months maintenance for $149 ($99 during the sales): you own the license, and you get 12 months of updates (like a one time purchase)
Whatever you chose, you can activate the trial version once you own a license, by going in Help->Manage license.
Cheers,