Modules of affiliate programs work just as well as content modules. It means you can search for items on the page of post editing and add selected items to the post. But for affiliate programs is very important to keep products up to date, so you can specify in the settings of module - option "Automatically update". This is time in seconds, then the module will make a product search again and update products on the site.
Now, in order to product list is automatically updated after a specified period of time, it remains to specify keywords for search. This field is called "Keyword to automatically update". If the field is not specified, products will not automatically update.
In addition, some modules of affiliate programs are able to update not only all products completely, but also it can track the price and some other information about already added products. The parameter is called "Update Items" in the module settings.