WooCommerce Dynamic Pricing & Discounts v1.0.18 lets you manage product pricing rules and cart discounts easily. Features and flexibility are not matched by any alternative.
Version 1.0.18, April 8 2015
[*] Fixed cart discount not being displayed on product quantity change
[*] Fixed "coupon invalid" warning when the last item is removed from cart
[-] Removed option to apply discount after tax (not available since WooCommerce 2.3)