FreshBooks is a Mac compliant, online invoicing and time tracking service designed for small businesses and independent professionals. Version 3.6 now includes account credits. With account credits, users can now allow their customers to pre-pay for services and track how much credit each customer has available at any time -– eliminating the need to maintain manual records. Credits also enable users to automatically track account balances to quickly get an accurate snapshot at any moment. Packages range from free to US$39 per month.