Fishcouple: No, it doesn't cost extra to feature items within your own shop. If you click on the star, that item will appear at the top of page 1 of your shop under "Featured Items" (as you have noticed in other sellers' shops). It will also appear wherever else you currently have it situated in your shop. This is a good way to forefront items that you want shop visitors to notice; however, it doesn't effect Etsy relevancy rankings like paid promotion does.
