If you are a home user (not commercial/educational/government)
You get SPAMfighter Pro 10 days for free. After the 10 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 10 days for free. After the 10 days, you can pay US$29.00 for 1 year's subscription or you can uninstall SPAMfighter.