1. If you think that the static pages you create will automatically update then you are wrong. Only dynamic pages (Categories, Tags, Archives) created by the software will update automatically.
Though there is only one dynamic page in a blog for posts and we cannot post to more than that one page, we can create the appearance that we have posted to more than one page. We organize posts by assigning categories to them. You can create a custom menu and add the categories into the custom menu.
Here’s a link to a custom menu walkthrough > http://onecoolsitebloggingtips.com/2011/08/11/wordpress-com-custom-menu-walk-through/
There are many common errors, misunderstanding and misconceptions when creating custom menus and you can read about them here > http://wpbtips.wordpress.com/2011/12/19/custom-menus/
2. You cannot advertise any product you do not personally create or any service you do not personally provide. Aside from a blog being accepted into WordAds http://www.wordads.co/ no blogger initiated advertising, retailing or reselling the work or products created or services provided by anyone other than yourself is allowed on free hosted wordpress.com blogs. E-commerce transactions via shopping carts and the like cannot be conducted on free blogs from and being free hosted by wordpress.com
There is no upgrade you can purchase from WordPress.com that allows blogger initiated advertising on a free hosted WordPress.com blog.
If you do require an ecommerce site, advertising and/or affiliate links you can hire a web host and get a free software install from http://wordpress.org Refer to > http://support.wordpress.com/com-vs-org/