NO. You only pay for the products once. (unless otherwise stated)
If you attempt to try purchasing again Apple will alert you that you've already purchased the product and will unlock it for free.
Alternatively, make sure you're signed in to the same iCloud account you originally bought the products on and tap 'Restore' to restore already purchased products.
For more information about how In-App Purchases (IAP) work, please visit Apple's Overview.