Create a free Salable account if you don't already have one.
From the settings section of the Salable dashboard create a new API Key.
From the settings section of the Salable dashboard create a new payment integration.
Replace the API key on line 20 of js/client.js with your Salable API key.
Add your Salable API key and product UUID to the pricing.html config.
Add your Trello API key to the script in index.html.
Get to it my friend!
Back in the Salable backend, create a new product. You can call this whatever you want.
Add a "Delete" capability to the product you just created.
Create a plan and add the new capability "Delete" to it.
Create more plans if you intend to offer paid and free versions of your Trello Power-Up.
Now go integrate your new Trello Power-Up and watch the money roll in!