PayPal Error Message: "This transaction is invalid."
Please click here to checkout again. This will usually resolve the error message you have seen.

If the above does not work, please contact us. We'll create an order for you and send you a payment link. Although these payment links also send you to PayPal, because no cart details are provided through them they tend to be checked less vigorously by PayPal and thus resolves the "transaction is invalid" error.