Free Invoice & Billing Software for Windows & Linux
Accounting & Best Practice Business Administration System
Simple Invoicing program for Desktop written in vba and Access
Accounting system for smaller companies written in GnuCobol.
Free Bootstrap 4 admin/dashboard template
Small Business Appliance
Libertya Electronic Invoice
Fullstack open source Invoicing application made with MongoDB
Open Source Invoice Programm for Egroupware
Best software solution for Small, Medium Retail shop Management
Mutasyon is a script can add customer, products, inventory or invoice
Free web-based invoicing primarily for Finnish companies