The most effective framework for this is what Justin Viles calls the "transaction moment" on eCommerce Fastlane. It’s the idea that you can create new revenue opportunities by promoting complementary products to your customers right after they’ve trusted you enough to complete a purchase.
The first step is identifying the right partners. You're looking for what Justin Viles describes as "non-competitive but complementary offers." If you sell skincare, you could partner with a brand that sells silk pillowcases. If you sell home-brewing kits, you could partner with a custom bottle label maker. The goal is to build what one Shopify Masters episode calls an "Ecosystem Development," where a network of businesses supports a shared customer base. Your product and your partner's product should feel like a natural next step for the customer, not a random ad.
Next, you have to apply this at the right time. The "transaction moment" is key because it’s a high-trust window. The customer has just bought from you. An offer from a partner you recommend on the thank-you page or in the order confirmation email feels more like a helpful suggestion than an intrusive advertisement. This is how you can leverage the 'transaction moment' to generate what Justin called "instant, incremental revenue" without disrupting your primary conversion flow. It