Simple Invoices is a free, open source, web based invoicing system that can be installed on a local server, hosted/cloud environment or even your laptop. Also add to an existing LAMP server which is what I did.
Some of the features:
- Absolutely free, no monthly subscription
- Browser based application you can use from anywhere
- It’s open source, developed by the community and it’s yours
- Easily track your finances, send invoices as PDF’s and hundreds of other great features
More details and download: