Progeny Apps / Pricing, offers & checkout / Twain
For shopify merchantsA discount that fires only when two named products are both in the cart — on every Shopify plan, and tested against sample carts before it goes live.
Twain gives a discount when the cart holds product A and product B, or A, B and C, or any one item from one group plus any one from another. Take a percent off, an amount off, or set a fixed price for the set. Each rule has test carts that must and must not get the discount, and it cannot go live until every one is right. A cart tester shows why a rule fired or did not. A conflicts screen finds rules that would give the same items away twice. Shoppers one item short can be told what to add.
On its way to the Shopify App Store. Write to us and we will set your store up first - it is billed through your Shopify bill, like any app.

The problem
A discount that applies only when two named products are both in the cart, on every Shopify plan.
It answers the questions a merchant actually asks:
- Does this cart get the discount, how many times, and why (or why not)?
- Three coffees and two drippers — is that two pairs or three? (Two.)
- Do two of my rules give the same items away twice?
- Which rule gets the item when two want it?
- Did a rule quietly break because a product was deleted, or expire while still switched on?
What it does
Inside Twain
every rule in priority order: what the cart must hold, what comes off, Live / Off / Expired / Broken / Failed its test, and every warning in words.
name, checkout message, priority, most times per order, start and end dates, combines-or-not; the groups (products or single variants, how many per set); what gets discounted (one group, every item, the cheapest item, or the order total) and how (percent, amount off, fixed price for the set). Below the status sit the test carts: carts built from your products that must fire and must not. The rule cannot be switched on until every one is right.
pick or build a cart; see the total, each rule that fired (how many times, on which lines, and why), each that did not and why, the near-miss messages, and the exact JSON the Shopify Function would return.
pairs of live rules that want the same products: double-dips (critical), duplicates, and overlaps priority settles — each with the smallest cart that holds both and what it ends up paying.
stacking (each rule's choice, or never), which Function API, near-miss messages, the products (what read_products brings in), what gets published to the Function, look, backup and restore.


Pricing
One flat price
No tiers to decode and no share of your sales.
$6 a month
- Discount only when the named products are all in the cart
- Percent off, amount off, or a fixed price for the set
- Test carts must pass before a rule can go live
- Finds rules that would discount the same items twice
- Flags rules broken by a deleted product or past their end date
Billed through Shopify's own app billing. Cancel by uninstalling. Privacy for this app
Questions
The ones merchants actually ask
Which Shopify plans does it work on?
Works on every Shopify plan.
How am I billed?
$6 a month through Shopify's own app billing, on your normal Shopify bill. No card is taken here and there is no share of your sales.
What happens to my data if I uninstall?
Shopify tells the app the moment you uninstall, and the app erases what it kept for your store. Customer data requests from Shopify are answered the same way. The full detail is on the app's own privacy page.
Is it on the Shopify App Store?
On its way to the Shopify App Store. Write to us and we will set your store up first - it is billed through your Shopify bill, like any app.
Who do I talk to?
A person, at support@progenyapps.com or (541) 208-6685. FHL Stephens LLC, Roseburg, Oregon.
Twain, $6 a month
A discount that applies only when two named products are both in the cart, on every Shopify plan.


