If you want customers to checkout with more items, try creating product bundles that cost less than if the same items were purchased individually. By bundling products, you're effectively increasing the perceived transaction value.
You can create bundles in minutes with Dropified. The entire bundle will be ordered in one step even if the products are from different suppliers as long as they are AliExpress or eBay suppliers.
Create unique bundles that your customers will want and watch your profits increase without any more effort.