We do not see any free options at this stage and have searched the main site for the cart
Link: https://shopplugin.net/features/cart/
We also found some info that you could use to develop (write code) your own export to Google Base (which we accept) here
https://shopplugin.net/api/shopp_googlebase_spec_map/
Trouble logging in? Simply enter your email address OR username in order to reset your password.
For faster and more reliable delivery, add support@myshopping.com.au to your trusted senders list in your email software.
A code was sent to the recovery email address. Please provide the 6-digit code.
A code can be retrieved from your authentication app. Please provide the 6-digit code.
An email was sent to your recovery email address. If you need further assistance, please contact your system admin.