When your customer makes an initial purchase, you have an opportunity to add to the sale by promoting additional products or services. This is called cross-selling. You also have an opportunity to persuade your customer to purchase an upgraded version of the initial product or service they purchased. This is called upselling.
Take every opportunity to cross-sell and upsell to your customers. If you have a brick and mortar business, place visual cues in strategic areas such as waiting rooms, entry and lobby areas, restrooms, dressing rooms, near your check-out counters, and in dining areas. Every customer "touch" point is an opportunity to cross-sell and upsell.
In the digital space, display similar products to the one your customer is viewing or purchasing, and if applicable, promote packages that offer an increasing level of components... and value.