I offer many different designs, and sell them as mix-and-match sets (of 3 or 12 cards). I rely on people to manually input the particular cards they want in their set in the Special Instructions box at checkout.
Obviously this is a process fraught with error and oversight. I want to streamline this! What I would like to do is showcase all the cards, either on separate product pages or in some sort of master gallery, and have people select which designs they'd like... then, as they add more and more cards to their cart (or to some pseudo-cart interface), the interface tells them: "Add 1 more card for a discount..." or "Now you qualify for a discount, add 5 more cards for the next discount" and so on.
In other words, the interface allows them to choose exactly which cards they wish, and how many... and depending on the quantity, it automatically applies certain tiers of discounts. I as the seller then get the exact info of which cards they bought, and the buyer doesn't have to remember to type anything at the end. They also get to create their own multi-packs, and see the discounts applied as they do so.
Can this be done? Is there some obvious solution I'm overlooking, or are you a savvy developer who knows just how to make it happen? I'd love to know your thoughts and get bids on this job. Please contact me at store [AT] wondermark.com, subject: "Shopify store." I'm happy to answer any questions, as well.