Final answer:
The statement that partner-friendly apps are free for Shopify Partners to use on stores with a paying plan is false. Shopify Partners usually have to pay for app usage on live stores, similar to other users.
Step-by-step explanation:
Partner-friendly apps are not necessarily free for Shopify Partners to use on stores with a paying plan; this is false. Although Shopify Partners may have access to development stores to test and develop their apps, when it comes to using apps on a live store with a paying plan, they typically have to pay for those apps just like any other user. Partner-friendly apps can also refer to apps that provide additional benefits or features specifically for Shopify Partners, but it does not inherently mean that these apps are free.