GnuCash - A personal and small-business financial-accounting software, licensed under GNU/GPL and available for Linux, Windows, Mac OS X, BSD, and Solaris.
Zoho Invoice - 100% free online invoicing software for small businesses.
Ledger-cli.org - Ledger is a powerful, double-entry accounting system that is accessed from the UNIX command-line.
Bill.com - Bill.com provides ACH payments processing, automates your accounts payable and accounts receivable processes.
Free Invoicing Software - Free Invoicing Software provides the facility of online billing.
Wise - Currency exchange Banks and other providers could charge you up to 5% in hidden costs when sending ...