BILLmanager is described as 'Highly customizable billing software for hosting and IaaS business with the full scope of functionality for billing, service provisioning, client management & support' and is a popular Billing System in the business & commerce category. There are more than 50 alternatives to BILLmanager, not only websites but also apps for a variety of platforms, including Windows, Linux, Mac and iPhone apps. The best BILLmanager alternative is Summit Finance, which is both free and Open Source. Other great sites and apps similar to BILLmanager are Autumn, Invoice Ninja, FreshBooks and WHMCS.