For the examples below, why do the firms price the way they price considering factors such as monopolies, price discrimination, pricing strategy, tying, or bundling?

Why are there sales after Christmas? The usual explanation is that stores are trying to get rid of excess inventory before the spring season.

Why is it so cheap to buy a season pass at Six Flags? If you walk up to the ticket window on a summer day in 2019, you will pay about $83 for a one-day pass to the park. That price does not include parking, discounts on concessions, or any "VIP" upgrades. If you go online in April, for $78 you can buy a pass that will allow unlimited entry into the park for the entire summer. You will also receive several upgrades, free parking, and other discounts. Why?

Why do firms sometimes deliberately make their products less useful? Many software companies produce a "student version" of their main product. This version lacks several key features found in the full version and so is less desirable and so is sold at a significantly lower price than the full version. This seems odd because producing multiple versions is always more expensive. Why?