Here's the Deal

If you are a home user (not professional/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 (professional//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.