When should I register?
Stellaris is shareware. This means you may download the software free of charge. You may use the software free of charge for an evaluation period of 30 days. You are required to pay for the software only if you continue to use it after the evaluation period has ended.
When you register the software, which involves paying a licence fee, you receive a license file that contains your personal key code. You may then copy the license file to the installation folder, and its presence turns the installed software from an unregistered copy into a copy that is personally registered to you.
Even in an unregistered copy, all features are fully available without restriction. There are no 'nag screens' or other reminders that you are using an unregistered copy.
How much does it cost?
The fee is USD 20 or EUR 20 per license. You can choose :-)
How do I register?