WP-Invoice is free plugin which has a lot of helpful functionality and helps a lot of people send invoices to their clients.
I have mentioned that you can use point as separator for cents like this 1’000.67. The only issue which you have is that you can’t set comma. Is that really big issue to set 1 star to the plugin? All other staff is working correctly. You could change your opinion for more high rating.
Our plugin is fully translatable. You can find documentation how to translate plugin here – https://www.usabilitydynamics.com/product/wp-invoice#documentation=translating-plugins
Regards.