The MPack toolkit has received a fair amount of media attention, causing it to become one of the most desired Web browser exploit toolkits in the underground hacker scene. The original author was selling the MPack toolkit for $1,000 USD, including a year of free support, and additional exploit modules for around $100 USD.
However, considering the toolkit is written in a script language, it is easy to redistribute and modify. The toolkit is being sold by others now for as low as $150 USD. That is a whopping 85% off. Talk about clearance sale. The sellers likely didn't even need to buy it themselves, but rather probably found some of the multiple Web sites that did not employ standard Web site protections, allowing them to download the whole kit for free.
With the toolkit available in the underground scene and even available to almost anyone for a mere $150 USD, its usage is likely to grow. In addition, without a single author controlling the distribution of the toolkit, we also expect to see forks of the source code with additional exploits, bug fixes, and other feature enhancements.