Here’s another very common technique: the shipping costs are free for the buyer, but the merchant has already included them in the selling price of the product.

This technique is more risky because it increases the final price of your item, and therefore potentially puts you in a higher price range than your competitors.
On the other hand, it can be considered on items that already have a high price (shipping costs are often lower compared to the value of the product) or on exclusive products, suffering from very little competition.