Finally it will give you a price to add to your cart with qty. the price can be generated from matrixes from excel
I created my site on Shopify, and have something similar.
There's an app that let's you do quantity breaks. I'm paying $60 per month for it. $30 for the Shopify site.
So $90/month for what you're looking to do.
I went with Shopify because I didn't want the headache of my site ever going offline. Being offline for a day would cost me a lot more than what I pay for the site for a year.
It's not cheap, but it's functional and "worth it".