You can pay here

(Enter invoice amount at PayPal website)

RSG Prototype Service accepts payments through PayPal. You can use your PayPal account or a major credit card. Please note that due to PayPal’s security policy, your payment amount may be limited by the balance of your PayPal linked bank account or credit card spending limit. Please click on the button above which will bring you to the PayPal website. Fill in your invoice amount to process your payment. Thank you.