Custom catalogs aggregate base catalogs, set special pricing rules, and let you override other fields, while preserving the original base catalog. You can also use Custom catalogs to create language-specific catalogs and sale catalogs
Custom catalogs support price rules. That is, you can specify whether the price for the category or product is the same or different as the price in the base catalog. For example, AdventureWorks.com sells a line of camping gear. The Adventure Works Company could include all their products in a single base catalog with retail pricing. However, they might also want to sell their camping equipment to their distributors at wholesale prices. In order to sell their equipment at wholesale prices to their distributors, they can create a Custom catalog based on the original base catalog. The Custom catalog can include special wholesale pricing rules that apply to the products in the base catalog. They could also create other Custom catalogs with retail pricing for their different sets of customers.
You can combine catalogs and products to appear as a single catalog to the customer. For example, you may want to create a manufacturer-specific catalog. You can add products from several base catalogs, selecting only the products from a specific manufacturer. You can then offer views of the Custom catalog to different types of shoppers. For example, a large retailer can aggregate all their vendor catalogs into one Custom catalog, and then offer views for Home, Business, Government, and Educational classes of shoppers.
You can display prices in a different currency than what is used in the base catalog.
You can focus on a specific subset of products. For example, you could create a spring catalog or a summer catalog. You can then offer views of these catalogs to your different types of customers such as "big-spenders" or "budget-conscious spenders. The smaller catalogs make it easier for customers to find items on sale.
You can obtain catalogs from several small vendors and then aggregate them into a Custom catalog. You can then create views on the Custom catalog, which you present to different sales channels.