WP-Invoice is a free plugin from Usability Dynamics. You can find it here:
The current invoice system only allows adding invoices to customers. I would like to add an additional plugin that allows supplier invoices to be shown in a similar way to customer invoices but this would then show as minus amounts in categories and totals.
It needs to be a separate module allowing normal upgrade of the wp-invoice plugin.
When applying if you send me a list of websites you have developed etc without specific reference to this plugin I will delete the email and not respond to you.