Free billing software for linux

actiTIME project is a Web-based standalone time tracking system that is streamlined for billing and management purposes. You can keep track of the time worked for your customers and projects.
Several configurable reports allow you to analyze the collected time expenses in different ways and get comprehensive and clean data for time management purposes. It integrates with QuickBooks accounting software.
Main features:
- Time expenses are recorded on by-customer and by-project basis
- Overtime and undertime calculations and reports
- Co-workers can share information using daily task comments
- Support of billable and non-billable task statuses
- Explicit reports for billing and management purposes
- Individual access rights management
- Entering/Modifying the time-track of other users
- Integration with Intuit QuickBooks
- Data export in the CSV format
- Access to the system through a web browser
- Support of different database platforms
- Runs under most operational systems
- Free of charge
Enhancements:
- The ability to rename hierarchy levels was added: Customer, Project, Task.
- Performance was improved and a memory leak on the server related to user session data was fixed.
- There were more than 30 small fixes and improvements.

Main features:
Scheduled Transactions
- You can now create recurring transactions, including automatic reminders when a transaction is due, the ability to postpone a scheduled transaction without canceling it, and the ability to specify only a limited number of transactions.
Mortgage & Loan Repayment Druid
- A guided dialogue for setting up loan payments as scheduled transactions.
Small Business Accounting Features
- Simplify managing a small business with Customer and Vendor tracking, Invoicing and Bill Payment, and Tax and Billing Terms.
OFX Import
- GnuCash is the first free software application to support the Open Financial Exchange protocol that many banks and financial services are starting to use.
HBCI Support
- GnuCash is the first free software application to support the German Home Banking Computer Information protocol, allowing German users to perform statement download and initiate bank transfers and direct debits.
Improved Import Transaction Matching
- The development of OFX and HBCI support has also resulted in an improved transaction matching system that more accurately recognizes duplicate transactions during file import.
New User Manual and Help
- A new help subsystem that focuses on how to do tasks is now available, in addition to a Tutorial and Concepts guide that gives the user background information on accounting principles and how they are reflected in GnuCash.
New Multi-Currency Transaction Handling
- GnuCash no longer requires separate currency exchange accounts to handle multiple currency transfers. Transactions can be made directly between accounts denominated in different currencies.
Redesigned Menus
- The GnuCash menus have been redesigned to conform more with the new GNOME Human Interface Guidelines.

Regulus is a accounting/billing/monitoring product dedicated to ISP market, its Real-Time capabilities are unique and allow ISP to really manage, control terminal server and WEB access by Internet users.

Regulus project allow ISP To boldly go beyond the break-even point and become more profitable.

FreeMED is a Web-based medical records (EMR) and patient management system with a printing system, patient scheduling, an HL7 interface, a billing system, XML-RPC Web services, and many other features.
FreeMED has an extensible modular architecture, allowing it to be customized based on individual practices without having to rewrite core components of the system. It is HIPAA compliant.
Enhancements:
- NPI support (used with newer version of REMITT), initial superbill support, enhanced billing logic and better billing behavior, a DHTML viewer for Djvu documents, additional community documentation from freemed.info, many bugfixes, and incremental module improvements.

Interna is billing software that is able to manage customer-related and product-related data and statistics.
The document managment is able to generate the types quotation, order confirmation, delivery note, invoice, and credit advice in English and German.
Enhancements:
- The startup scripts are only provided as Linux shell scripts.
- The software has not been tested with Windows yet.

FreeNIBS is a loadable plugin for FreeRADIUS radius-server.
FreeNIBS provide authorization/authentication/accounting for Dialin (PPP/PPPOE/PPTP) users.
It can bee used for real-time prepaid and postpaid billing. FreeNIBS can bill users on service accuration, time, traffic and time&traffic.
FreeNIBS has very flexible settings for groups, users and prices. All data store in SQL-databases such as MySQl, PgSQL and Oracle.
FreeNIBS is covered by the GPL license.
Enhancements:
- Build error with FreeRadiuses 1.1.5-1.1.6 was fixed

Printbill is a sophistocated Unix print billing and/or accounting system with associated administration utilities. It primarily supports LPRng but now has limited CUPS support as well.
A simple print filter and accompanying daemon perform pre-printing billing, post-printing billing, print-accounting and print job quote generation. In addition, various utilities for administrators and users are provided - including programs to check your print quota and usage patterns, a web interface for both users and administrators and a command-line quote generator.
Charge rates may be specified on per-page, per-percent-coverage or both, and any number of printers/print queues can be provided (with different charge rates and printer parameters). Monochrome and CMYK colour printers are supported (with separate charge rates for both colour and black ink).
For all filters, processing can happen out-of-order, and you may prioritise jobs on the basis of size (jobs larger than a threshold can get lower priority or higher priority as desired) and jobs are billed in parallel / overlapping - jobs which finish billing first get printed first.
This is not necessarily the same as the order of arrival. Detailed stats are collected on a per-printer basis for job size, CPU time for each job, page count and ink/toner coverage, so you can analyse the usage patterns for your printers and predict when a cartridge will need to be replaced. It supports an optional user-supplied anything-to-postscript filter, so you can get properly billed for plain text, DVI files, image files, and so forth as well as PostScript.
Databases and configuration files may be stored on a centralised web server. This allows read-only access so that Unix (and conceivably Windows) clients could easily check quota, calculate quotes etc. remotely.
For fun, an additional filter is provided which allows users to deduct fixed amounts from their accounts (we use it to let students buy drinks and food from an unsecured laboratory fridge).
Enhancements:
- Finished support for per-user per-printer stats, tested that it works.