I'm currently running a grocery/mini mart store on Shopify, and would like to offer the following services for our customers:
1.- Volume discounts on some products (this is attainable via various apps).
2.- Bundle discounts on products of different categories (i.e. oreo cookie + soda) This is also attainable via various apps.
3.- Bundle discounts on products of the same category, but the bundle needs to be dynamic (i.e. we have 7 types of head and shoulder shampoos, if a customer wants 1 shampoo it costs 3$, if he wants 2 of any flavor it is 5$). Haven't found any app that could do this, but maybe i'm looking in the wrong direction.
You can create a custom solution for this as long as business rules are clear it will be easy, it gets messier when you have multiple apps as well as your own custom rule. In such case, you need to visualize all possible variations of a cart and decide the priority for discounting