One job: make the volume discount and the best value per tub impossible to miss. Here are three concepts for GymDough's box builder, each modelled on a shop that nails it. Same real flavours, same real pricing (£6.50 a tub down to £5), three different ways to shop it.
Modelled on Eat Surreal's build-a-box
Add any mix and watch the price per tub fall as the box fills. A tier ladder and a tray that fills with real tubs make the saving and the per-serving value tangible. No cap: keep going past six and every tub holds at the best price.
Modelled on Magic Spoon's custom bundle
Pick a box size, then fill it to the count. A big "3 of 6 in your box" meter and one flat box price turn the discount into a bundle you complete. The cleanest, most guided path from empty to a full, best-value box.
Modelled on Duradry's multipack page
A classic product page. Choose a pack from cards that each show the price per tub and what you save, add a subscribe-and-save option, pick a flavour mix, and go. The fastest way to land on "the six-pack is the best value".
#demo link for a mid-build state and a #complete link for a finished box, handy for a walkthrough. Everything is GymDough's real catalog, macros and pricing ladder. No checkout is wired; the add-to-cart buttons are demos. The subscribe-and-save option in concept 3 is illustrative of the pattern, not a live GymDough offer.