Avast say they have an XP version free that you can try https://www.avast.com/windows-xp-antivirus
From my recollection it will probably prompt you occasionally to buy the full version, but you can simply ignore the prompts or pop ups and accept them as the price for a free product
AVG also say they have an XP version https://www.avg.com/en-gb/windows-xp-antivirus
AVG was recently taken over by or merged with Avast, so it might actually be the same product that I previously linked to
Are you asking for help with removing some sort of virus or malware form your computer or is this just a general post asking about what AV is suitable or available?
From my recollection it will probably prompt you occasionally to buy the full version, but you can simply ignore the prompts or pop ups and accept them as the price for a free product
AVG also say they have an XP version https://www.avg.com/en-gb/windows-xp-antivirus
AVG was recently taken over by or merged with Avast, so it might actually be the same product that I previously linked to
Are you asking for help with removing some sort of virus or malware form your computer or is this just a general post asking about what AV is suitable or available?