Free, cross-platform and offline-first invoicing solution that syncs.
Invoice At Once - Easy Invoice creation.
Slimvoice - Insanely simple invoicing
Simple Invoices - Never Wait For Clients To Pay You Again!
Envoice - Send invoices and get paid on Paypal, Payoneer, Stripe and Square.
Zoho Invoice - 100% free online invoicing software for small businesses.
Invoice Ninja - Invoice Ninja is a free, open-source solution for invoicing and billing customers.