What is the very simplest commerce cart?

@coykiesaol asked for the very simplest cart and replies from @fionix, @rashida11, @ecmcircle, and @pgmco cover heavier and lighter options. For absolute minimum fuss, choose a hosted, embeddable checkout or "buy button" approach that handles payments and security for you. It only needs product info (name, price, image) and an email or webhook for orders. No server maintenance, no PCI scope if you never capture card data on your site.

Quick practical checklist you can follow today:

1. Make a short product spreadsheet (SKU, price, weight if shippable).
2. Create an account with a hosted checkout provider and add those products.
3. Configure notification email and webhook URL so orders land in your inbox or a simple app.
4. Place sandbox/test orders to verify emails, receipts, and shipping calculations.
5. Embed the button or link, test on mobile, then flip to live mode.
6. Add SSL to your pages or rely on provider-hosted checkout pages.

Tradeoffs and tips: hosted checkouts are fastest but incur transaction fees and limited customization. Self-hosted carts give control but need updates and security work. Always test in sandbox, check spam folders for confirmation emails, verify webhook endpoints, and confirm currency/tax settings. If you later need subscriptions, complex shipping, or many SKUs, validate demand with a simple button first, then migrate to a more feature-rich setup when justified.