BundleTiers adds a simple bundle selector to your product page: 1 pc, 2 pcs, 3 pcs, each with its own price, saving and badge. The discount is calculated again in the cart and saved on the order, so what the customer sees is what they pay.
What it does
yourtheme/bundletiers/selector.php.Which products get bundles
Bundles are off by default and are switched on per product (Product data BundleTiers Enable bundles). Simple and variable products are supported. Grouped products (a page that lists other products) and external/affiliate products have no BundleTiers tab: enable bundles on the individual products instead.
How the tier is chosen
The tier follows the total quantity in the cart, not a saved choice. Changing the quantity on the cart page updates the discount straight away.
Privacy
BundleTiers does not connect to any external service, does not track visitors and does not collect or send any data. Everything runs inside your own WordPress site.
Source code
Development happens on GitHub: https://github.com/webbeblabs/bundletiers