Manager!

GnuCash is personal and small-business financial-accounting software, freely licensed under the GNU GPL and available for GNU/Linux, BSD, Solaris, Mac OS X and Microsoft Windows.

InvoicePlane is a self-hosted open source application for managing your quotes, invoices, clients and payments. The application comes with various options, templates and settings to customize your invoicing experience.

HomeBank is a free software. Use it to manage your personal accounts. It is designed to easy to use. Analyse your finances in detail using powerful filtering tools and graphs.

Mint.com is a free web-based personal financial management service for the US and Canada.

BILLmanager is a linux-based control panel for automating client management, invoicing and billing. This software specifically developed for hosting service providers will help you manage and take complete control of various aspects of your business:

FrontAccounting is a simple, but powerful, system for the entire ERP chain and covers:

The easiest way to track and forecast your wealth - using a calendar. Put all of your income and expenses on a calendar so its easy to see your daily balances, when bills are coming out, get reminders and see where your money is going.

The most popular version of Americas #1 small business financial software helps make your business more profitable.

Invoice Ninja is a free, open-source solution for invoicing and billing customers. With Invoice Ninja, you can easily build and send beautiful invoices from any device that has access to the web. Your clients can print your invoices, download them as pdf files, and even pay you online from within the system.

FusionInvoice is an open source invoicing, quotes, and client management application built for freelancers and small businesses who need a simple, yet powerful self-hosted web based invoicing system. FusionInvoice is community driven so ideas/features, help/support and more is all provided by the project developer and various dedicated Fi users.

webERP is a complete web based accounting/ERP system that requires only a web-browser and pdf reader to use. It has a wide range of features suitable for many businesses particularly distributed businesses in wholesale and distribution. It is developed as an open-source application and is available as a free download to use. The feature set is continually expanding as new businesses and developers adopt it.There are on average 5,000 downloads per month.

Gnuaccounting is a Free Java cross-platform accounting and bookkeeping application.