Pricing Your Product
How we tripled our revenue by adding one button
Here's an example where raising prices of individual items also raised the perceived value, which makes the bundle seem like an even better deal. The convenience of a bundle increases the customers' incentive to buy, even as the average order increases.
Freemium Software - A Guide for Startups
Jules and Daniel methodically lay out a case for the freemium business model. Read this if you're asking whether freemium is right for your product/company.