Ted here from Shopify. :-)
Have you recently made changes to the price within your Shopify admin? If so, it can take Facebook up to 48 hours to fully sync these updates. Facebook's Debugger tool can sometimes hurry this process up though -so it's a handy link to save in your browser.
If you're still experiencing issues with this, could you link a product from your Facebook page and let me know what the correct price should be? I'm more than happy to help!
Thanks a mill,