Promotion: Free fanny-pack on orders over $100 [has estimate]

## Features

### Customer Requirements

[See wireframes for promotions here](https://docs.google.com/presentation/d/1bFMezSqqTuMyzOGR0P8H-neSNuwZEsmxgYAKG9mcuq4/edit#slide=id.p)

__Happy Path__

- Customer is able to see the fanny-pack promotion on the homepage
- Customer clicks the fanny-pack discount and is prompted to add the fanny-pack to the cart
- Customer adds the fanny-pack and promotion to the cart
- Customer sees a warning about needing $100 to use the promotion.
- Customer adds $100 of value to their cart.
- Customer checks out
- Customer sees the promotion on their receipt

__Refund Case__

- Blah Blah Blah

__Customer Removes Promotion Case__

- Blah Blah Blah

__Customer Removes Fanny Pack Case__

- Blah Blah Blah

### Administration User Requirements

- Administrator is able to create a fanny-pack promotion
- Administrator is able to disable the fanny-pack promotion

## Out of scope

- We will only support free-items given some minimal order amout.
- Promotions not exist for some "timeframe", a administrator will need to enable and disable.
- Promotion will be available once per order. It will not be limited to once-per-customer.

## Epics 📝

- Promotion - Provide a list of promotions for the user
- Promotion - Receive a list of promotions
- Administration - Build and publish discounts
- Cart - Enable a promotion to be added to the cart
- Cart - price the promotion
- Promotions - Verify if a promotion is available
- Order - Place an order with a promotion
- Promotions - Consume the promotion
- Order - Send the promotion to the store

Start with the linked promotion wireframes and compare them with the Customer Requirements, Administration User Requirements, and Epics in this issue. Clarify the unfinished refund and removal cases, then trace the promotion flow from listing and cart pricing through order placement and receipt handling. Done should cover the stated happy path, administration actions, and agreed edge cases.

Written by the indexing model from the issue text.