I need a "Quantity break" app but at the same time I need to provide some partners with coupon codes.
I noticed that the apps tend to occupy the coupon code field.
Any solutions for using both?
You can offer quantity discount via app Selly.
There is an option to display discount code input on cart, so that if customers also have a discount code, they can apply it right here.
Probably the easiest way to do exactly that is with Bold Quantity Breaks. It does not force coupon codes in, nor does it duplicate products or variants :-) https://apps.shopify.com/quantity-breaks
Full disclosure, I am one of the founders. If you have any questions on it, happy to help!
Here is an example of what that could look like on your shop. Keep in mind, the front end design is 100% customizable.