Correct if I am wrong, but AVG Anti-Spyware has a 30-day free trial. If you subsequently dont't buy it...then it still functions except that Updates have to be downloaded manually, and the Resident Shield is not active....you need to do periodic manual scans.
I presume that is what you mean by real-time protection.
A word of caution, In the current issue of PCadvisor is an articel called "Too much Antispyware"?
Extract"...unfortunately, Windows allows applications (including Spyware..sic) interfere with one another and affect the stabiliy of the whole system..." and "...Any XP PC is likely...to become unstable".
One of the more well heeled forum member (I cant recall his name right now) reported a guy having 14 !!! anti-spyware apps running.