Here's the Deal

If you are a home user (not commercial/educational/government)
You get SPAMfighter Pro 30 days for free. After the 30 days, you automatically downgrade to the 100 %free SPAMfighter Standard.

The difference between SPAMfighter Pro and Standard are explained here.

If you are a business user (commercial/educational/government)
You get SPAMfighter Pro 30 days for free. After the 30 days, you can pay US$29.00 for 1 year's subscription or you can uninstall SPAMfighter.

The differences between SPAMfighter Pro and Standard are explained here.