4. Now Is the Time to Slip in an Upsell or Downsell

Step 4: Now Is the Time to Slip in an Upsell or Downsell
After the prospect has turned into a customer by buying your main product offer, offer one or more offers designed to enhance the value of the main product offer, known as upsells and downsells.
Upsells are shown immediately after the main or previous product was purchased and are only available for that price at that moment; if the person leaves the page, the upsell deal is gone. Downsells are shown immediately after an upsell offer is rejected; downsell offers are either the same upsell offer for a lower price or a slightly-reduced offer (one or more elements of the upsell offer is missing) at a lower price.
Upsells and downsells are not required to be purchased to get the value and benefits to the main offer; they are only optional purchases to enhance the value and features/benefits of the main offer.
Having a combination of upsells and downsells in your sales funnels will increase the chances for conversions and additional profits.
Most Internet marketers make the bulk of their profits on the back-end of the funnel (i.e. upsells and downsells), not from the front-end of the funnel (i.e. main product offer).