Antivirus software companies like Norton and Kaspersky give free versions of their basic software. These companies also offer 30-day trials of their more advanced products. If the user wants to keep the full product after the trial period, he has to buy the product code or serial number.
GiveawayoftheDay.com also offers a free full-version software everyday. The software creators participate in the giveaway in exchange for publicity and feedback from users. In order for the free license to work, users must download and install the product on a specific date. However, the software downloaded from the website does not include technical support nor product updates.