Selleasy is a Shopify app that offers one-click upsell and cross-sell features to increase average order value. It allows you to create upsell offers manually or through automatic product recommendations. With Selleasy, you can display "frequently bought together" bundles, cross-sell product addons on the product page, pop-up a cart upsell funnel, show post-purchase upsell pages, and cross-sell related products on the thank you page. The app supports multi-language and multi-currency Shopify stores and offers assistance with setup.