Hi I have a requirement, In quote while adding products if I select a product, for example, a coffee cup it should show the rate of 20 if I choose both coffe cup and a water bottle then my coffee cup rate should reduce to 15, I have tried hard to get this requirement solved if anyone can help me out that would be great full

I have a Page layout of NPSP Customized it and I am trying to deploy it to production but I can't able to include it to the Outbound changeset I can't even see it in the add changeset components I don't know why Please Help me to sort this issue