Do you want a customer to complete checkout for 1 product and then after checkout get pushed to a custom offer or product page for an upsell?
This plugin for WordPress and extension for WooCommerce allows the admin to designate a custom thank you page. When a custom thank you page has been set for a product, upon checkout the customer will see the order completed page for only a few seconds and then will be forwarded to the designated page. The custom thank you page is set in the product page settings as shown here:
You can easily set the custom page by inserting any custom URL or be selecting an existing WordPress page from the dropdown menu.
NOTE: The redirection will only work when a single product is in the cart upon checkout and that single product has a redirect field page designated. If there are multiple products in the cart, regardless of any custom thank you page(s) that have been designated, the default WooCommerce page will be loaded and no redirect will take place.