Creates new unpaid order and returns checkout_url for the customer along with download_token for the application
Unique identifier of the order in the customers application
ID of the model in the CGTraders system
Email of the buyer. CGTrader guest account will be created if user with given email does not exist. However if access token is authorized by user (3-legged oauth authorization was made), buyers_email parameter will be ignored and authorized user will be treated as a buyer.
On successful or failed purchase customer will be redirected to provided url with two parameters:
id - order ID in CGTraders system
uuid - unique identifier of the order in the customers application