BoxBilling is a free billing and client management application. A commercial version with expanded functionality is also available. Box Billing was initially released in 2011. With BoxBilling you can sell any product imaginable - web hosting, software licenses, servers, downloadable products and setup any custom products.

Features:

• Supports automated billing, invoicing, product provisioning
• Automatically create hosting accounts as soon as the payment is received
• Suspend when account becomes overdue, terminate when a specified amount of time passes.
• Enable multiple currencies, accept one time and recurring payments
• Boxbilling is perfectly created to sell
• Shared and reseller hosting accounts
• Domains
• Software licenses
• Downloadable products
• Custom recurrent billing products
• Helpdesk, knowledge base, news and announcements system.
• Intuitive Web 2.0 AJAX powered interface with 100% usability score!