So these guides put Shopify next to Etsy, Wix and WooCommerce on cost, setup and who each one fits. Each one says plainly which kind of seller should pick which platform.

A straight answer for someone who has never sold online, with the real fees and the real sign-up screens.

The cheapest plan that can take payments costs the same on both. What differs is what the site is built to do.
WooCommerce's software costs $0. A store built on it still has a monthly bill, and it comes with more work.