At the moment I can not afford to spend money on a lot of the great options out for invoicing and was wondering if the community knew of any free or open source options out there.<p>Some of the features I am looking for:<p>Input your business info,
Input client info,
Input project details and cost,
Generate invoice PDF,
Generate receipt PDF,<p>Bonus:<p>Ability to mark&#x2F;track who had paid and outstanding balances.
Ask HN: Free/Open-Source Invoicing Software?