Our website shows real-time stock availability - i.e if we have a product in stock if you can add it to your cart. If what you want is unavailable or not listed please contact us - more stock may be coming or we can probably get what you want in for you.
You have copied the placement for the Product Page.
Go back to the App Embeds section, and in the Paypal Advanced Settings, paste the copied value into the Product Page field and click the 'Save' button in the top right corner.