AgileBill is a Flexible Billing and Invoicing Application for a number of markets, including Web Hosts, ISPs, VoIP Providers, and membership/subscription type models. It features numerious plugins for payment processing, provisioning, and interfacing with a variety of 3rd-party applications and services.
cP Creator is a totally Free script which provides an all in one management system for the budgeting free, paid host. It's a totally robust script which has been developed from the ground up to provide hosts an all in one system without the monthly price tag dragged along. cP Creator is a system which packs some groundbreaking features into one free box.
Freeside is the premier open-source billing, trouble ticketing and provisioning automation software for wired and wireless ISPs, VoIP, hosting, service content providers and other online businesses. The list of features include: flexible pricing and rating plans including anniversary billing, pro-rating, usage based billing and more. Plug-in system allows easy addition of new pricing plans. Also is avalaible real-time credit card and electronic check processing with all major processing gateways.
PHPCoin is suited for anyone that needs to track clients, support requests, orders and invoices. PHPCoin provides additional CMS functions such as articles, contact forms, FAQ, content pages, site search, admin defined side menu columns (customized down to the individual link for access by all, client, or admin) and much more.
It is a free application that was originally written for web-hosts. Nevertheless, PHPCoin is very versatile: it is used by accountants, lawyers etc.
The Hosting Tool is a very new script, launched in December 2008 claiming to provide the next generation in free, hosting scripts. It provides the webhost complete automation on almost everything: signup, monthly posts checking, suspension. Also, it provides client features like the client control panel that gives the power to the clients hands in what they want to do. They can check their monthly forum posts, edit their details, check announcements.